"Hi, I read that some Tau players don't play Tau anymore because they think that the units in the codex are so much more expensive (regarding points) than the 5th edition codexies. Because of this unbalance it's not fun to play Tau they think. Do you agree, are Tau units that expensive compared to 5th edition codexies?
In short - yes, Tau are over-costed and showing their age. Are they not fun to play? Hell no. I will admit, I stopped playing my Tau in 5th mainly because they got repetitive for me and as 5th edition and tournaments have evolved (i.e. NOVA), their issues with midfield and holding objectives have become more paramount.
With your regular BRB missions though, Tau can still be quite a force with a lot of shooting potential. There are a lot of units you wouldn't really consider because of their price or lack of usefulness but there are an array of units which are good and relatively speaking, costed appropriately, which put together can make pretty solid lists.