Depends on what you use it for
Any AR from the big 4 (Bushy, ArmaLite/Eagle, colt or Oly) will be just fine for general purpose use.
For a DCM gun, I would have to give the edge to ArmaLite. Out of the box, the ArmaLite trigger is better than the Bushmaster, but a Jewell is the best trigger to install.
The ArmaLite comes with a nice Wilson stainless steel barrel that is very accurate, though not as long lived as a Krieger.
Also, Bushmaster glues the front site base to the barrel, whereas ArmaLite has started to use an adjustable front sight base. This adjustment allows you to adjust the zero windage by rotating the front sight base, much as you get the initial elevation zero by moving the front sight post up or down.
My ArmaLite NM AR that I bought new in 1998 required 1 minute of left windage to get a zero on a calm day. Now that's not much, but if you require 2 or 3 minutes of windage to zero, you may run out of windage on a windy day at 600 yards. The rifle shot 3/4 moa and was a contender until about 2500 rounds, when the barrel throat ran away on me and I could not seat 80 gr bullets out far enough. Still shot like a demon with mag length (2.250" OAL) ammo, though.
CLE makes their outstanding uppers with 4 allen screws (two on each side) retaining the front sight base, which means you loosen the screws on one side, tighten them on the other to move the base to get your zero, tighten them all then forget about it.
So, here are my preferences:
1)CLE upper w/ Krieger barrel, on anybody's lower, with a Jewell trigger (about $1700).
2) ArmaLite NM, box stock, about $1300, be prepared for a back order
3) Bushmaster DCM