Hydralisk 's DPS and Range + Infestor's Fungal growth (4 sec can't move) = best combo? Hydralisk is very afraid of Colossus and Siege Tank. Infestor's Neural Parasite => defeat Colossus? Infested Terran => defeat Siege Tank?
No, they're not. Infestors have baneling humour which hydras can't really stand. They pair well with roaches who don't really give a crap about it. Source: http://www.banelingbbq.com/?comic=9[/ur] [url]http://www.banelingbbq.com/?comic=10
In PvZ it shouldn't work because there's nothing to tank for you but in ZvZ it does quite well. You need to add brood lords though.
I think RoachInfestor is better in terms of practicality. For one, Roaches have tons more HP, so they can tank while the Infestors work their magic (so to speak). They also have less range, meaning they'll move closer to enemy units and give the Infestors room to Neural Parasite while still being behind them. They're crappy DPS is compensated for by the Infestor's Spells and their cost-efficiency; you can make SO MANY of them for so little cost (relatively speaking). HydraInfestor is a more powerful mix, capable of ripping through enemy armies like butter, but the ball dies just as quickly and is much more expensive to replace. Initially, go Roaches and Infestors. If you have the money, go Hydras and Infestors. If you have the micro, go all three and rape everything.
Personally, I go Roach+Hydra and then near end-game I start building up some infestors to help with the madness. It works pretty well in Bronze (Which I can not get out of D: )
Roach + infestor is more viable since roaches can tank. Not to mention the comp is still adept at good DPS.