Desc440 has kindly started a Blood Angels codex review for us all to enjoy. Everything written in the following series of posts is by him and published with his permission. I've added a few counter-points and some editing but all the core ideas are his! Enjoy.
Dante : Good
The head honcho of the Blood Angels. Seems fitting to start with him.
Clocking in at 225 pts, Dante isn’t cheap, but he’s a good character regardless. First and foremost, he makes Sanguinary Guard Troops. This lets you manage your Elite slots more easily, while making your Shiny Boyz scoring as well. I guess you can also use Dante to create the NippleWing (all Sang Guard army), but I’m not a big fan of that personally.
As for Dante himself, he is a decent combat character with three important rules. The first is that thanks to his improved Death Mask, he can nerf an enemy IC before the game, making it lose 1 Wound, 1 WeaponSkill, 1 Initiative and 1 Attack. Having enemy Librarians die to their first Perils test is rather humorous but I prefer to apply the curse to big, scary combat characters to make them more manageable. The mask of Sanguinius also functions as a normal Death Mask, which we will cover in the Sanguinary Guard entry.
Second of the three important rules is Tactical Precision, which allows Dante and his unit to avoid scattering completely on the Deep Strike. Not only does this have direct benefits (usually one very dead tank when Dante arrives) but additionally, this can influence your opponent’s choices during deployment, sometimes leading him to make an overall bad decision just to minimize the damage of one unit. Just be careful not to fall into a trap laid by your opponent; just because that juicy Chaos Land Raider is a tempting target doesn’t mean it’s a good idea to DS next to it if Oblits get a clear line of sight to Dante and his boys in the process. a great and often overlooked bonus of this ability is reliable deep-striking a Sanguinary Priest into the battle. That little D6" scatter can often make ensuring deep-striking units are within FNP/FC range annoying at best and Dante's no-scatter rule can really help land a Priest where it is needed.
Finally, Dante and his squad also get Surgical Strike, which gives them Hit and Run. This is pretty huge for an army that works on Furious Charge. It also helps to avoid getting tarpitted by hordes/dreads, especially when Dante is accompanying a unit of Sang Guard who doesn't afraid of anything.
Dante works well with shooty Honour Guard by helping them avoid getting stuck in combat where they cannot shoot. That being said, I find the best unit to put Dante in remains Sang Guard, as they get the most out of his abilities. He can also alleviate the small squad size issue and the fact that they lack an invulnerable save (useful to suck up the odd plasma shot thanks to 4 wounds + Iron Halo). He lacks Eternal Warrior though which is a bit annoying against Power Fists and the like so be careful!
Seth: Bad
Much like the Flesh Tearers are fairing worse than their parent Chapter, so too does their Chapter Master compared to Dante.
So what is it that makes Seth bad? Well, he just doesn't do much for the army as a whole. He has no army-wide special rules, he doesn't unlock an alternative FOC and beyond his Fearlessness, doesn't even boost the squad he's with... and it's questionable wether Fearless is a boost in the first place, really.
On top of that, he's not even really that good a combat character. His bigass chainsword is entertaining, but beyond being a Dreadnought deterrent and possibly instant-killing Klaw Nobs, doesn't really do much a power fist wouldn't do as well or better. His sucker punch rule, while certainly fun, doesn't have much of an impact in the grand scheme of things. Yay! I killed an extra Ork or two! Truely this is a game-changer!
He's hard to fit into most Blood Angel armies as well without that Jump Pack which leads to him being left home more often than not. Therefore, unless you're making a fluffy FT list, it's probably best to pass on Rippy McRipper.
Astorath: Average
Astroboy seems deceptively good at a first glance: he's handy in combat, he boosts his squad, he increases the likelihood of squads getting Red Thirst and he even unlocks the DC army. However, under close scrutiny, Astorath loses some of his glitter. While I'm not going to knock on his combat abilities and squad boost rules, as they are good, I think its important to take a minute and ponder on his other selling points.
Firstly, I must state what is probably obvious to many: Red Thirst isn't very good. Getting Furious Charge and Fearless one in six times does not compensate for losing the awesomeness of Combat Tactics. Additionally, you're bound to be getting FC regardless due to Sanguinary Priests (which also give you Feel no Pain) and Fearless is often worse than ATSKNF anyways.
Ergo, Astorath's Shadow of the Primarch rule is not that great in most cases. Now consider that Astorath unlocks multiple squads of DC (which already have FC and Fearless by default) and it becomes clear that there's inefficiency hiding in there somewhere.
Speaking of DC armies: please don't do this. At least, not as your main army. Having no scoring Troops and being unable to control anything in the movement phase is pretty fail.
When you take into account the aforementioned points, Astorath just doesn't make the grade to be considered a great character. However, he still has enough going for him that saying he is outright bad would be fallacious. Just be aware of his shortcomings and go from there. Sometimes he will indeed be worth it (off the top of my head: an army with a lot of infantry-based ranged firepower would benefit substantially from Fearlessness while having a decent combat char for counter charges).
The Sanguinor: Bad
I tried. I tried really hard to make him work. I tried because I like the concept of a bad ass avenging angel of death swooping down from the skies and wrecking bloody havoc on the enemy. Sadly, it was not meant to be.
Before I tackle what makes Sangui bad, let's cover his strong points. Firstly, he's obviously handy in a fight. This is considerably more telling when pitted against his chosen target. Secondly, he does give a nice boost to your assault elements in the form of +1 attack to all units within 6 inches. Thirdly, he gives a nice little boost to one Sergeant within your army. Not exactly a game changer, but still nice to have.
Now for the bad part: despite his 2+/3++ and Eternal Warrior, Sangui isn't very survivable. Because he is not an IC, he can't hide in squads. He only has T4 with 3 wounds. How hard is it to kill 3 Hammernators again? Tough, but not THAT tough and in 5th edition it's not that hard to put a bunch of wounds on a guy. For a 275 pts character, this is a hard pill to swallow.
His aura is only 6 inches. This is problematic because to get the most out of your expensive beatstick, you will have to bunch up somewhat and be aggressive. Playing passively with a 275 point paperweight puts you at a disadvantage obviously. A 12 inch radius would have been more sensible considering his cost.
Finally, the blessing is determined at random. Boosted Hammernator sergeant – awesome. Boosted Devastator sergeant – not so awesome. I've seen people game this by taking Dante AND Sanguinor, using only Sang Guard as Troops (because they don't have a Sergeant) and taking a lone Vanguard Vet squad with hammer/shield sarge so that he automatically gets the blessing. My comment on that is: are you guys for real?
As much as it saddens me, I can't say Sangui is good. I would have liked to though, trust me.
Mephiston: Excellent
Ah! Finally, the big bad wolf himself, Mephiston!
This guy just oozes win. Let's take a look.
First, he is a beast in combat: assuming he gets all his powers off, you're looking at six S10 WS7 I7 attacks on the charge that re roll to hit. In addition to that, the Transfixing Gaze rule makes him quite adept at bitchslapping enemy Independent Characters. And Mephiston has a huge threat radius thanks to Wings of Sanguinius + Fleet, so he gets to apply all that combat ability fairly easily.
Second, he is highly survivable. Like Sanguinor, he is not an IC. Unlike Sanguinor, this is ok due to having T6 and 5 wounds. While he can't join squads, he can still use them to gain cover saves against shooting. And he is easy to hide since he is a small model. When in combat, he has little to fear aside from power fists, which is a problem easily fixed with multicharges. He does however lack an invulnerable save which is a major weakness. If he gets caught in the open or a squad of power-weapon/rending/etc wielding nasties which survive him, watch out.
Thirdly, and because Jesus loves you, Mephiston also brings utility to the army in the form of his psychic hood. If he also had Shield of Sanguinius, he would pretty much be an auto-include in most army lists (and I guess this is the reason he doesn't have it).
There's two minor gripes I feel I should mention: one is that because he is not an IC, he can't ride with squads in vehicles. This is not too bad in most cases thanks to his easily-hidden model, but when anti-psy is cancelling Wings every other turn, poor Mephy often finds himself wishing he wasn't so anti-social.
My other gripe is that since he doesn't have the ability to work with DoA due to his lack of a real jump pack. However, you can't have everything, and Mephiston remains a very, very good HQ choice for a vast percentage of competitive BA lists.
Captain Tycho: Bad
By far one of the most interesting characters in the Blood Angel lore, Tycho unfortunately suffers from his lack of focus.
Afflicted with jack-of-all-tradeness, Tycho is both decent at shooting and at combat. While this is not always a bad thing, when putting a 175 pts price tag on it, it is.
Rites of Battle, while in no way a bad rule, simply doesn't have such a big impact on 5th ed Blood Angels due to mandatory sergeant in every squad. If you use Combat Squads a lot, RoB becomes much more valuable, but on the whole, it simply fails to leave much of an impression.
All in all, Tycho has the makings of a decent character, but his price tag drags him down considerably.
Oh, right... you can also choose to use DC Tycho. Why you would do this, I have no idea.
Conclusion
It's pretty obvious but Dante and Mephiston are really the best options available to a Blood Angels army. Mephiston is pretty easy to fit into any army and is one of the few characters which adds little to the army outside of being a beast in combat. He's just that good in combat he's worth the cost. Dante on the other hand is like many of the new 5th edition special characters and adds to the army as a whole. He's still pretty handy in combat himself but you are generally looking to take him for Sanguinary Guard as Troops with his other abilities as a bonus.
The other characters just don't benefit the army for their points or aren't so flash in combat. These guys are often hard to fit into the army effectively and aren't always going to improve the army.
