I don't see what's so great about the m4a1. Because sometimes it can be TOO acurate for me(yes I just admitted that I do not have a perfect shot. So sue me!). Whenever I use it, I always miss and people are able to kill me right away. Besides you can still hear an m4 CLEARLY with its silencer on. BUT with ak 47 its got a slight spray and deals way more damage than m4 and I'm just addicted to the sound that ak47 makes.
i like the ak, its very strong, cheap and very accurate.
the m4a1 is to expensive and doenst make any damage (dc u realy most work at the m4)
Funny seeing as both does about the same damage. I would advise you to test out the weapons on a local server instead of a remote one since the latency in the current cs2d is very sensitive.