Quote (BardOfXiix @ 5 Nov 2012 20:33)
They don't understand the place ultras hold. Much like people who QQ about Roach OP don't understand the place roaches hold.
Ultras are a momentum unit. If you play hyper aggressive and have a big advantage from dealing damage, go ultras and rely on your momentum to win. This is basically what Life does. He's super aggressive early game, usually gets to get some good damage in on his opponent with ling/bling pressure, then uses ultras to run them over (not giving them time to recover). Broods take a long time to build corruptors => morph broods => move across the map. They are stronger in a fight but the time it takes to ready them can allow for an opponent to struggle back into the game.
The other purpose that most people use them for is tech switch against mass AA, making Terran vikings useless. And that is a good reason to use them too.