Thats an exceptionally expensive rifle. You can get a gas AR15 for that price if you want.
If you spend over $800-900 on a stock AR15 that you build yourself, you're doing it wrong. you should be able to built a top 15% AR15 for that price and then take your time upgrading it. Only things higher end will be the noveske's and top end rifles (or piston rifles)
Piston rifles are a fad, no more. At least with the AR15.
I would put Daniel Defense, Noveske, LMT, S&W and similar uppers and lowers as being FAR better in quality over what has been linked here.
My rifle - the VTAC 2 - costs so much due to its parts:
$250 Geissele trigger. Best trigger on a rifle I have felt to date. My 1903 comes close, though.
VLTOR stock, that's another $130 or so?
$400 or so troy front hand guard
A good flash hider that directs gases forward
Melontied barrel, NOT chrome lined
1:8 twist, which is better than 1:7 or 1:9.
Sling mounts that are $50 off the shelf
A light mount also $50 or so off the shelf
Is it expensive? Sure. But compared to my friends Daniel Defense quad rail gun, this thing is great. Insanely light. No major tinkering. No hunting for parts.
Edit: Oh, and let's not forget, S&W service. Which is amazing, and worth an extra bit of money up front on the gun. $900 for a bare bones AR15, or 1900 for a nearly perfect gun. Seems like a simple choice.
Changes I want:
Buffer tube quick detach
pistol grip with palm swell
Leupold 2.5-8x illuminated mark 4 scope
Surefire Scout light
Front grip with spot for flashlight pressure switch
More ammo. You can never have enough.
Maybe a beta c mag too...