I don't understand the people claiming Oblivion wasn't good looking for its time. It was not just good looking for its time, it was good looking for some time after it came out too (and it still looks great to me)! It needed some hefty hardware to run well relative to the time it came out.
Oblivion was very good looking for it's time, most professionals said it was the best looking game at it's time with loads of content, yes a 20 hours game with small levels would look better but it's not a fair competition.
And yes the trailer confirmed to be xbox360, rendering it on a pc with two gtx 580 would look better but someone on internet would catch it and all hell would break loose.
I say it looks far better, far more detailed, the forest scene is not much better but another style and also look less uniform. Forests around Bruma looked worse than around Anvil.