I have 2 Chiappa uppers and never had a problem with them. Keep them lubed like a regular upper and it will last a very long time. Accuracy and reliability are both very good. One has a poly lower so it's very light and suitable for the grand kids to shoot.
I have a DPMS .22 upper. It is aluminum and steel. It uses Black Dog mags. So, far it is 100% reliable with high velocity and standard velocity ammo. It is far more accurate than I expected. The finish is a perfect match for my lower. I have also heard good things about the CMMG unit. I got my DPMS .22 upper from MidwayUSA. With my birthday discount, it was a good deal. I had to get on the waiting list, because these units sell out quickly. Midway notified me when one was available. Here is a link to the one I have: DPMS AR-15 AP4 A3 Flat-Top Conversion Upper Assembly 22 Long Rifle 1
+3 for CMMG. I've got a rifle length PRI CF forearm on mine. Currently it has the Millet DMS glass on in. I've shot it using both the grey CMMG and Blackdog magazines. I prefer the Blackdog ones. Just make sure to check the feed lips, they crack if you're over aggressive.
Tactical Solutions AR22 M4. Actual Cerro Forge upper, actual M4 contour barrel. Nice BCG design. Eats anything I feed it. 1" groups at 50 yds with average ammo, 1/4" groups with of all things Lapua Match.
I have a Chiappa upper also, and am very pleased with it. I bought it a couple of years ago for $275 and have shot a couple of thousand rounds threw it with no problems and it is very accurate. I put Magpul furniture on it and it looks great.