Here's some more thoughts after a little more playtime:
-Shooting feels okay, but I still think it could be a little 'tighter' across the board. The gold standard for console FPS's is still Halo in my eyes, and the shooting in Halo: Reach feels excellent to me (despite complaints about reticule bloom). Maybe just a touch more aim assist/magnetism and making hip-fire a little more useful. Now I know Resistance is Resistance and Halo is Halo, but Resistance is still pretty similar to Halo in both movement speed and player damage resistance.
-The Auger is ridiculous, especially when you've got the other team spawn trapped into a building.
-I've already said some on the Body Armor attribute, but I think it almost totally negates the Carbine and the Bullseye. After unloading roughly a whole clip of Bullseye rounds into an Armor wearing player, he killed me and on the kill screen he had only half of his health eliminated.
-The Spotter ability coupled with the Marksman is great. I think that's a great combo of weapon and ability. Speaking of the Marksman, I feel like the bullet spread maybe a little too random at times. I'll have to use it more and that may be by design, but I feel it might be just a tad to much spread.
-Spawning with a Sniper Rifle is one of the things I've hated the most about games going the Call of Duty, loadout route. I absolutely hate having several guys sitting in dark buildings in the back and just picking me off with their Deadeyes. It's especially annoying when it seems like the sniper is able to kill in one shot regardless of where the bullet lands. I know it's probably just me being slightly down health, but with all the leapers running around hitting me and me being pegged from random places, the sniper is very deadly.
-While it's pretty easy to tell when your bullets are landing on the enemy, it's pretty tough to tell where you're being hit from/if you are even being hit. Sometimes I can tell easily that I'm getting hit, but it almost seems like the reactionary sounds cut in and out and the directional hit markers aren't that obvious sometimes. I'll have to keep playing to put my finger on what I think is the problem and an idea for the solution.
-Movement and jumping could use some tweaking too. The movement speed itself is decent, but the actual 'feel' of the movement could be a little better. Going back to Halo, I think Halo 2/3 has a great sense of feel and movement speed. Jumping in the R3 beta is a little too short as some others have already said. The players should be able to easily jump waist high barriers.
I've been getting my ass kicked pretty good, but it's decent. Maybe it will be like the UC3 beta and I'll start to enjoy it a lot more once it 'clicks'. I'll keep playing and have more to say later on.