Yes I would recommend either of the units as far as reliability, quality and accuracy goes. The TAC-SOL AR-22 shoots right with my Anschutz when benched. Like I said I haven't benched the AR-57 as yet just shot from the bi-pod with the red dot at 25 to dial in the red dot and green laser and didn't have to make any adjustments as both were where I thought they need to be and the gun fired 20 rounds into an area about a bit larger then a quarter, but not as big as a half dollar.
One thing I really like is the ability to tie a cloth bag around the magazine well on the DPMS and collect my brass for possible future reloading.
As far as will my AR-57 fit all uppers, I asked the same question and the guy at the shop I bought it from put the upper on and cycled the action on DPMS, Colt, Bushmaster and one lower with just four or five letters that I never heard of but was nice looking without any cycling problem. I realize that is not a complete test, but was good enough to show it would work on any platform that was mil-spec unit.
I hope to get it out to the range next week to bench rest the gun and see how it does at 25, 50 and 100 yards. I always do a 25 yard sight in then when shooting beyond 25 yards adjust for rise and or drop out to what ever range I shoot. I am limited to 100 yards at the gun club here and and that should be about the max I would ever use the gun, anything else I will step up to my Browning A-bolt 222 or the Browning FN 257 Roberts that I have popped feral dog at 450 yards with in years past with the Leupold 7.5 x 55 AO scope.
Now the real plus is I have a pistol and rifle that use the same ammo, rifle using a commercial P-90 magazine that holds 50 rounds, with a training upper that is also blow back operated and makes for cheap practice.
