I have had awesome experience with the 2 butler creek barrels I have on my 10/22s. One is a carbon fibre, and the other is a 20 inch non fluted.
When I bought the 20 inch, I read everything I could online, and they were getting very bad reviews online. I figured for the price I'd try them anyway. Long story short, the rifle will often put 10 shots into 3/4-1 inches at 100m over and over again, with my girlfriend shooting. I get slightly better from time to time. At 50m, it is a hole.
The carbon barrel is almost as accurate, but I find it a bit tough to shoot due to the lack of weight.
I have not experienced any wandering zero, or crappy groups, or anything else like that. I shoot american eagle hollow points almost exclusively, and never bothered with an ammo test with the barrels. The AE stuff was fine, and cheap. I have both barrels mounted to unchanged 10/22s for two years (in june and july). I have never seen one that did not shoot first hand, which is directly in contradiction with internet chatter. I would recommend one.
If you are in YYC, you are welcome to check mine out.