I haven't played Battlefield, so I can't say anything about it.
But still, these two games are totally different. You can't compare them in full. You can only compare parts of them, barely.
You're friend can say he like the game better, but he can't say it's a better game. Especially not if he haven't played BF 3 or Skyrim yet.
After looking at the http://www.youtube.com/watch?v=wi2tae2PmmU I must say it looks great, graphics-wise.
The most impressive thing about it is the
lighting. That's pretty comparable with TES, and only that, since lighting exist in Skyrim too
Crysis also had some wicked lighting. Very natural looking.
I haven't really been fond of the lighting in Skyrim, based on what I've seen so far.
Take this for example: http://www.platformnation.com/wp-content/uploads/2011/02/The-Elder-Scrolls-V-Skyrim-DARGON1.jpg
The lighting is pretty bad on the snow and very bad on the sky.
I definitely think lighting is one of the things that should be improved/tweaked/changed before 11/11/11.