My apologies for digging up an old thread. The SR22 was the first handgun I ever purchased. I had no experience with a firearm, and .22 seemed like the kinder, gentler way to get started.
Mine is probably ten years old now, and has been essentially trouble free. It came with two magazines. One had a slightly odd bend to the feed lips, and was a bit of a chore to load properly. Ruger replaced it no questions asked. I've since purchased several additional spare mags for it, and all have functioned flawlessly. It is the firearm I use to train all my children.
It does have the occasional FTF, which I expect is perfectly normal for rimfire. Quite often a second strike will set off the round. If not, tap-rack-bang always works. Mine will cheerfully eat Reminington RGBs, Winchester M22, Federal Champion, and of course CCI Mini-Mag. Basically, it's happy to cycle anything that isn't subsonic. It will fire the subsonic just fine, but you have to rack it after every shot.
I've heard of the issue you described with the takedown lever. I ordered an allegedly "indestructible" polymer replacement part, but never got around to installing it. I never needed it, as my factory original part has never broken. I'll see if I still have it in my parts drawer, and I'll let you know where I purchased it.
Sorry to hear yours is giving you trouble.