Worth the upgrade, AMD HD5870 vs GTX 660/670?

Well seeing as these cards were just released I was wondering what people think of how much performance gain I will get from switching. I got this AMD Radeon HD5870 card because I was in a crunch and it was on sale cheap, I much prefer NVIDIA(specifically EVGA cards) but I wouldn't just switch for minimal performance gain. I prefer either Newegg, Amazon or CompUSA. I plan to, if suggested, upgrade within the week.

My PC Specs:
ASUS Sabertooth 990FX
AMD 8150(stock clock)
G.Skill Ripjaws 2x4gb
AMD Radeon HD5870
Corsair GS700
Win 7 64bit Home

I mainly play Battlefield 3 at 1080p on Medium and record sometimes using Dxtory. I get constant 30fps recording(set in Dxtory) and 50-70 playing on average. I also use Sony Movie Studio to edit/render video clips. I don't have any current plans to SLI but possibly farther down the road?