If I had $1500 to spend, I would buy a cheaper one and buy as much ammo and decent optics I could for it.
Big + 1. I agree wholeheartedly.
It depends a lot on what you want it for. In all honesty, any name brand AR will likely outlast either of us with proper maintenance. Especially if you stick with one of the big names.
Olympic Arms, DPMS, Bushmaster, RRA, Colt, LMT, etc.
If you haven't checked out Olympic Arms, I highly recommend them, though a lot of folks will jump on the bandwagon and bash the brand to no end on internet forums, my 2 Oly's perform probably a little better than my Colt where accuracy is concerned and both have been just as dependable, but they don't offer a chrome lining option which for my needs, is unnecessary. I'm perfectly content cleaning my guns once in a while and I don't use corrosive ammo, so just because the Colt has a silver lining doesn't really make it better to me.

But Olympics lifetime warranty is a nice plus if I ever needed it.
What is important to me is reliability. Both Oly's have been 100% and to be fair, so has the Colt.
I also have a FrankenSBR made from a spike tactical lower and various upper parts that has been 100% also. The important thing is to get what suits you, learn to use it the right way, and it will take care of you.
DPMS, and Bushmaster, and Remington I have mixed feelings about right now because they're all owned by the same European company (cerberus). Myself, I prefer to buy American when I can, but that doesn't mean what they make (or have made) is bad stuff either.