I only switched over when PSN went down, and my cousin is on xbox so thats what I play now. Sucks that I pay for the live when PSN is free but I enjoy the "quality time" with family lol.
I ended up using a permanent unlock for the chicom and now I have diamond for the SMG's.
The chicom is quite an impressive gun with the reflex and select fire. I only get to use the diamond SMG's until i max them all out on prestige level 2 to unlock all the calling cards. Then i'm moving on to the assault rifles.
Its a shame because I think that SMG's are really dominant in this game, especially for FFA and run and gun style of play, the fun way to play lol.
I always found a decent rifle in the last 2 cod's. The commando and then the ACR, so lets see how going for diamond AR's works out for me. I'm an achievement whore, what can I say.
hardpoint is a pretty fun game type with good xp leveling to boot
i ran hardline along with UAV and counter UAV. hardline gets you the scorestreaks faster, and the UAV and CUAV each earn you more xp everytime a teammate gets a kill while they are in the air.
FFA is the best game type for headshots I have found, unless you like sitting in a corner waiting for people to run by to get that consistent headshot every time.
bloodthirst tip. run and gun until you get 3 kills. then lay low. the 4th kill will get you the UAV which will make picking up that 5th kill even easier without getting taken out right before you hit your goal.
the back double stairs on the carrier, and the low side on slums are my 2 best spots for picking up a bloodthirst streak. the middle of the map will keep you from your goal everytime unless you have dominant speed and are able to dodge bullets like the matrix (which happens sometimes, but not as much as the games that you empty a mag into someone and they still kill you)
