So, does anyone play coop? What are your devastating unit combo's with the various hero's?
Vorazun is OP when you use Corsair with disruption web and permacloak in conjunction with DT's and shadow strike.
Abathur's muta are REALLY strong when you get the 100% armored damage upgrade, I usually get 3 roach and 3 muta and play till those are evolved to brutalisk and the sky thing (I forget the name).
But I love playing with swarm host, upgraded to attack air and to deep tunnel anywhere on the map. Super fun to burrow in and dump a metric crap-ton of locusts.
Karax I usually just play with static defense, canon rushing as my ally goes in.
Raynor I do what I usually do with terran... BUILD MOAR MARINES.
Zagara - I rarely play her, often just mass up the explodey units.
Kerrigan I like to play with alone for as long as I can, then upgraded hydra.
Swann I like to build goliath and the mass carrier warp drop ship things. If I am on brutal I often upgrade to some thors. Warping all over the place and dropping a bajillion goliath is pretty fun.
Artanis is the least fun for me, but he is a great hero to have as an ally as that last second clutch invincibility ability is really super handy. Toward the mid late game with all upgrades you rarely lose units because of that ability.