I hav efinally decided to go ahead and get an optic, and decided on an EOTech, but now I need to know what the plusses and minuses are of the N battery versus AA battery versions.   I did look in the FAQ but the link is dead.

The AA battery version looks to be longer; will it fit on the top rail with a BUIS installed behind it?  I have no fore-rail and have only the stock handguard and ring.  Will this cause any problems?

How about battery life?  Cost of batteries?  Any other considerations I am missing?  Thanks!

The only advantage I see with the N is it's size and weight (it's smaller than the AA model)

Regards,
Gary

Thanks for the opinions!  I think I will go with the AA model if in fact it will fit on an A3 upper with a BUIS behind it , and not hang over and run into the handguards.

Quoted: The N models have had problems with heat from sitting in cars to long. The AA models have not. The AA model will fit on the A3 rail and yes a Buis will fit. I don't think the LMT CCH Buis will fit but all the others should. I perfer the AA models as the batteries last several hundred more hours.

IIRC, the N-battery models (511/551) also have problems in the complete opposite conditions also. I've heard that they don't stand up really well to the cold (a deal breaker for me. I like shooting in the winter because the snow is a reactive target at longer ranges and you can tell where you're hitting)

I got the 512 (I don't plan on getting NV) but haven't had a chance to go through a winter with it yet since I got it for my B-day in April.

WIZZO

I would get the AA model mainly cause the batteries are way cheaper and can be found anywhere

I have my AA unit mounted directly onto the flat top of my Colt Carbine just a hair short of touching the hand guards, and there's no problem using the ARMS buis, or operating the rifle. Buying that Eotech with the N battery  sure seems like a high price to pay to save an inch!