Zoanthropes. Points wise they can out perform fex's, taking out infantry and tanks with ease - if they hit. and now choosing 2 powers you can keep synapse coverage and still hack away at the enemy. they're protected somewhat with T.M., have a 2+ save with 6+ for pratically free. the powers just make them so flexible to a strategy. 3x Psychic Scream is very nasty, espicially to units trying to break from combat. Catalyst can stop Fex's from dying to assault termies and the like, and they can even screw up Libarians.
money wise they're cheap as well. and a very nice model to say the least.