On initial impressions, I'm a little disappointed.
Hopefully most of these are due to it being a beta, but we'll see...
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Lag (even on local servers)
Poor framerate (GTX285 in SLI with latest drivers and an i7 920 - yet I need to play on medium for a good solid framerate)
Guns are weak, pistol is stronger than most other things
As far as the Bad Company series goes, I found BFBC1 better.
The blur and sniper scope blur and all that cobblers is dreadful and unnecessary.
The login is slow, for the soldier anyway, may just be a temporary server issue though.
Guns are weak, pistol is stronger than most other things (I'm mentioning it again, because they are)