A very good game that can actually leave you wanting to play again.
I am by no means a Quake series fan boy, in fact, I barely even knew what the Quake universe was about before this game. Let me tell you right now that the framerates in NO WAY ruin the game. In fact, unless you're sitting there waiting for the game to slow down even just a little bit, you won't notice it as an issue at all. The single player is very smooth and very fast paced that will keep you on your toes quite a bit. You won't notice any issues really unless there is a huge battle going on, in which case, expect a little lag anyway. Overall, the guns as a whole are fun and easy enough for anyone to pick up and use, although each one does require a bit of strategy to use effectively. To go into more detail about the weapons, let's just kind of break them down. As you go through the first few portions of the game, you only have a few basic weapons such as the assault rifle, blaster, and shotgun, and the enemies really reflect these being relatively under powered in relation to the weapons you're using. As you progress deeper however, the enemies get tougher, and you weapons get more powerful and harder to effectively and efficiently get kill because of slow projectile speed as well as low rate of fire, just like any FPS. This also has no negative effect on the game.
Now those are just the weapons and single player, which is where the game really shines IMO. The multi player is less than fantastic and really leaves things to be desired. Although it is fast paced, it also seems to be based around a lot of ambush tactics, which basically means get behind the enemy, unload into their back, and you've got yourself a kill. This may not be true entirely, but that's just my experience with the online community.
Overall, the heart of the game really comes out in the single player. You may want to rent it first just to see if it is the right game for you, although if you can't find a rental, it's also a safe buy.