I love Battlefield 3 but I have two complaints: 1) It takes forever to get promoted/upgrade weapons and such. I'm still level 12 but I feel like I've played the game for at least half a days worth. I continue to use the same gun over and over because its the only one that I have all of the unlocks for. 2) It sucks that I never have a chance to upgrade my vehicles weapons. Whenever I get in a jet/helicopter I always fly around for about 20 seconds and then someone with an amazing anti air rocket immediately kills me and there's nothing I can do because I haven't unlocked the flares yet. Same goes with tanks and AAV's. I get destroyed in them without ever having a chance!
It does take forever to rank up. I'm at level 20 right now. Some of the rewards for ranking up the classes really suck, like unlocking the M16 for use by the Russians. That's cheap. If you unlock it, you should be able to use it whether you are American or Russian.