Which one is better? I have a Aimpiont M2 and a guy is selling a Eotech 3x for $300 bucks used, but I would like to know the diffrence if there is any. I dont like to buy used stuff but it seems like a good deal. I also would like to know how to tell a fake 3x Eotech vs the real thing. Thanks for any info. I checked Ar15.com and they only talk about the fake Aimpoint red dot's.