i too have one, for my g17, totally worth the money if you want to get range time with your glock to build muscle memory for it. i paid like 550 all said and done for mine..
it comes with a list of recommended and not recommended ammunition , id sugest to follow that as close as you can, i run blazer threw mine since all my other .22s love it (its on the not recommended list) it fires and cycles fine but the feed ramp leads up rather quickly, at about 200-250 rds i have to scrape it off.
id give it a 9.5/10, only becuase im not a fan of the rear site, i love that its adjustable but when it adjusts only a small portion of it moves and it takes abit of getting used to over the stock glock sites