I've used a White Oak Precision 24" unfluted upper, a DPMS 24" fluted upper and a light 20" unfluted upper. All happen to be .204's. All are amazingly accurate.
The 24" unfluted AR is a pig to carry and is somewhat slow handling but works OK in open country off a bipod or sticks. The 24" fluted barrel is much handier but I really like the 20" lightweight. It's handier to carry, handier to get in and out of the truck and quicker handling on stand. The lightweight still shoots less than 1/2 MOA at 200 yards. Its a Shilen barrel 'smithed by Dan Carey in Pheonix. I've pretty much tricked it out with a carbon fiber FF tube, Timney trigger (almost a must IMO) and an ACE M4 SOCOM stock.
If I were looking at a .223, I would consider the RRA 20" Coyote carbine. RRA has a great reputation for accuracy and you can customize it as you develope your own tastes and opinions.
I agree with the previous poster.."Everyone needs one AR in the family."