Madness:
It depends on which build you're playing against. Three color has issues with Keeper because the hyperaggressive nature of it is just weak against a deck with a decent amount of spot removal and pseudo-damage prevention via angel. The U/G build is annoying because they can cut you off from WW and can randomly block angel sometimes. Also, they can fuck with your balance, which is major frowns. This is definately not a good matchup, but their high content of blue stuff makes REB really good. Oh, also, Null Rod is mad annoying. Don't let that shit hit.
Hulk:
You NEED the third scrying, period. When playing this matchup I've come to determine that skillful application of Balance is the key to winning. If you can force it to resolve (much easier post board with rebs of course) then you can usually do enough damage to force a large Scrying through, and take control of the game.
If you intend to go mana denial, you really need to do so early. If you let them land two islands, you can walk right in to Gush.
SuperGro:
Er, eh? This isn't a problem matchup. GAT is strictly better against you because of Duress and the inevitability of active psychatogs, and even that isn't so bad. You've got a lot of spot removal and Exalteds that can gain more life than mystic enforcer can deal, as opposed to the 2G. Also, your spot removal is very diverse, so Meddling Mage doesn't really stop much of it. I don't see why you're having problems here.
Hope this helps.
EDIT: Haha, I got here first, Z.
