Crap yea, I meant to post about this a couple of days ago when I heard about it. Some people saying it's stupid to pay for the alpha but if you know you are likely to buy the final game, for ~20 quid it is a pretty damn good deal.
Not had the time to look into it myself but apparently it's looking good so far, but maybe that's just compared to the level of problems with the release version of Arma 2!
Have to say I am fairly tempted myself, and think I just about pass the minimum system requirements!
I quickly loaded it up and was happy to see I can run it (at the absolute minimum settings)!
Hope to get to test it at some point over the weekend, even that quick check had the memories flooding back of some late nights in ArmA II on Gav's maps!
3 copies of Arma3 Lite to give away - Try before you buy! just send me a request. Looks great, runs fantastically but haven't had time to properly try it.