Thrillhills's Roni thread motivated me to get one and I ordered a 9" barrel for my G22. Haven't shot it with the new barrel yet but I'm hoping it will move some of the blast away from my face and the extra weight should help with muzzle rise. The extra velocity can't hurt either.
I had to take the damn thing apart to get it in there so it's in there for a while, I won't be shooting the G22 alone until it comes apart again. Good thing it's a Glock! I bet it'll run a long time with the occasional blowing out with Gunblast or similar and appropriate application of lubricants just from the ejection port access. I'll have to check with CAA and see what solvents might be harmful to the polymer.
I left off the metal shroud at the muzzle because I like the look without it better, but at some point I might put it back because it did provide some structural support. It feels nice and sturdy without it though, I'll see how it feels under firing.
If I can prove to myself this provides an advantage over the G22 alone worth the extra bulk and weight it'll be a keeper. I'm not there yet. Now I need another G22 to compare against! LOL