The boogieman right now appears to be Aetherworks Marvel, and the only half-decent artifact destruction spell that can hit it is Fragmentize in white, as far as I can tell. Given that, it looks like white and blue (for counters) will be early favorites, but we'll have to see how things work out in practice.
I've played like 50 matches against 25 different people on beta and played an opposing Aetherworks deck once, not including divisionbyzorro.
White/Red aggro with Toolcraft Exemplar, Inventor's Apprentice and Bomat Courier (!) is what I'm seeing the most - specifically the big thing for the aggro decks is
Smuggler's Copter.
Someone did kill me by destroying Aetherworks with Appetite for the Unnatural, but that was because I had just used Aetherworks and put all 3 other Aetherworks on the bottom. You have a lot of scry so if they destroy one it doesn't *always* mean the end of the game. I mean you can miss with Marvel also.
I played a guy on Aetherflux Storm I couldn't beat at all in 2 games, but I suspect he just had great draws since I tried a variant on his list (I didn't know it but I knew all of the cards) and it was horrible.
Green/Black still a thing, but a lot of people aren't playing it because they want to brew.