The game is just superior to R2 in every way, don't want to go into detail as I am under the NDA and don't want to get in trouble.
I myself am a EU Beta Tester so got into the beta over a month ago and have been playing phase 2. Phase 3 is set to begin tomorrow so will be downloading the new code then so will be interesting to see what changes in any have been made. I played R2 WELL before I got the Killzone 2 beta so that must have improved a lot as well and am getting the new code for that again tomorrow, I will be able to give final impressions on both games tomorrow.