They are totally pointless. The majority of armies totally negate their primary advantage, which is fighting demons. They should only be used to bolster other Imperial forces.daemonhunters
Too many people play them. People have got used to tactics and can now beat easily. Not to mention they have no particular strengths/weaknesses, making them boring as hell. However, specific chapters can be interestingspace marines
Tau and IG are reasonably similar in playing style.
I just don't like these.tyranids
They require a lot of finesse and skill, I reckon they should be played as a third or fourth army. Not to mention they are really mean.dark eldar