I've played a bit over 2 hours of the beta, apparently. I wasn't around for beta 1 and unlike a lot of other fans I want this game to function well as a competitive shooter.
For the upcoming rant about performance, I have a 770, 16gb of ram and a 3.2 ghz cpu.

Starting off by being honest, the game is pretty good but it's not fun, its not fun because I cannot perform what I need to do (aim, move around, spray control, etc) and I cannot do a lot of that properly because the game runs like crap. What made insurgency feel so good was how fluid it felt, and if you had the skill to transfer a spray onto a target 180 degrees behind you to win 2v1's, you could. Currently I feel very crippled by the game. I'm aware you're starting on the optimisation stuff at the moment but the performance is stopping me from acquiring targets properly, all that nice stuff. If this isn't sorted out by release I don't think I can consider sinking much time into the ranked queue.
On the topic, the blur around the edges of the screen is so obnoxious, is that the post processing? that and the aliasing needs to be able to be turned off in my opinion. i feel like it's making the game appear very muddy and stopping players from really sticking out at longer distances.

Suppression, It was hated in BF3 and I think you'll find players who are not seeking total realism will hate it here too. I can understand giving a benefit to gunner classes to make their role more then just a slower rifleman, but being rewarded for missing was never a fun mechanic in my opinion, and furthermore it messes the graphic quality up even worse then it already is making it extremely difficult to return fire.

The end of round screen in Insurgency Source was very well developed, showing your personal stats as well as an MVP highlight, it showed off stats not relevant to the TAB screen like the shots fired by you and your team and was honestly pretty well designed. It sucks here, really badly. You have your defeat and score screen down at least - But these kinda half baked "cards" which appear in almost random spots, and convey next to no relevant information? It's kinda garbage honestly. There needs to be more overall thought into what those UI elements can contain and how they're displayed. Because right now it feels like it's lacking content.

Game balance, m4's maybe a little underpowered? it's hard to tell because of the game crippling performance. AK-74 doesn't feel as unique to the AKM like it did in IN:S imo. Also drum mags (that i tried in the coop mode) feel like they might be lacking rounds although I didn't test it out too much.

That's all I have for you for now, performance is getting in the way of me wanting to continue playing honestly.