I'd get it now, the only difference is the headset you get with the one from the shop but they voice chat support is crap in the game anyway so doesnt really make a difference.
Lol, talk about jumping down someone's throat. I downloaded it m8 as i thought it was a complete bargain. As previously stated, the voice support is pants.
I have been playing it for around two weeks now and have never needed a mic. Just get in there and kill, kill and then kill some more.