Well I have been playing story coop for 1.5 hours. Quick impressions:
-the game requires update as soon as you put in disc. The update says the file is 52MB but on the PS3 it was 2552MB under game utility file.
-the first load after update will take a LONG time. I mean like 5-7 minutes so be patient!
-the game froze on me already.

I was playing online with coop and the guy ended the game session and my screen froze so I had to hard reboot. The game has not frozen since (1.5 hours).
-PSN signed me out already! I read in the manual to open more ports in router so I have not tried on line since I open new ports and will keep you posted.
-no mouse or keyboard support from what I can tell.
-720p was upconverted to 1080p (looks quite clean if you ask me) via my AVR receiver, so the game will play and look good on 1080p.
-I am rusty so I am still learning the game buttons all over again. Options on in game. Character build is similar.
-game play and graphics are smoother. You can now sprint! But the graphics are clearly better than RB6-1.
-I do not notice any lag, or framerate drop but have not played long.
-has split screen
-weapons are similar to version one.
-grenade now uses circle button. You can configure buttons via tactical , southpaw, legacy...
-I had to crank the volume up but audio sounds good, bullets sound with a pop. Flash bang grenades seem to freeze you more than last version.
That is all for now...