I got my first full frame camera i also have a 7d as well. I am both happy and disappointed with it. The first thing is noticed is that I missed the 7d 19 point auto focus system like the 1d mark 3 has and the different screens like single point AF etc. This is a big drawback for me. I find it useful for macro work esp. the zone AF in Al SERVO mode is great gor moving objects. I have decided to use the 7d for macro work so there is less to crop.
I am happy with the noise performance of the 5d mk2 I intend to do a lot of night shooting and timescapes so this is useful esp. predawn and after sunset.
Another point is the external flash can only be used on board without a trigger cannot use it like the 7d but I do not see that as a major drawback for me as I do not do a lot of portrait or studio work.
I guess these are my first impressions of the 5D MARK 2 at a glance cannot wait to use it this weekend.