Yeah I've tried experimenting against the AI, just collecting cards of one faction during one play, to see how each one goes. These are just my inexperienced comments, and I'm terrible at the game, so feel free to correct me!
The Green (Blob) faction seems to just get the job done, with huge-damage cards along with a few that give you the crucial extra draws. I've not really found a downside to them yet
The Blue faction gives you a lot of money and healing, but no attack and no other extra draw, or deck-thinning abilities. The problem is that this faction just seems to bloat the deck a lot. By the time I have a decent amount of blue healing cards in the cycle, the enemy is doing tons of damage - and whatever those cards might heal is not enough to keep up.
The Yellow faction is interesting in that they have a lot of "make the enemy discard a card" effects, plus a few extra-draw abilities, and they have some decent attack - AND Recycling Center, which is a nice base to have, indeed. Making the opponent discard a card or two can make or break a devastating combo they might have waiting - if you're lucky. Without deck-thinning abilities, though, I have gotten stuck more than once with this faction.
The Red faction seems like it would be good - potent attack cards, lots of Ally attack abilities, Mech World, lots of deck-thinning - but I don't know. Something about it just seems to lack that extra push to get the job done.
So it seems you maybe need to mix the factions a bit? Unless you're playing Blob. Of course, the order that the cards come out in makes a difference, too.
I feel that this is a game where thinning your deck is not really that viable of a strategy. At least, against the AI, it seems like by the time you really get around to thinning, you're losing.
