I've only played MW2 MP from the COD series. I sucked when I started, k/d of much less than 1. I'm better now with k/d of 2-3/1.
I decided to try WaW just for something new and it's like I've never played a FPS before. I shoot people and they just don't die like they do in MW2.
Is it just the difference in games? I'm only at lvl 5 and obviously using starting weapons but I would've thought I'd be doing better at the start than I am. Also not that it matters but I'm only playing FFA so far.