I've got MkII, 22/45, and S&W M22A with 6" fluted barrel.
The more I shoot the M22A the more I like it, but.... While take down is easy, putting it back together again is best done with three hands. The mag release is in a goofy location (ambi which is good) but is very easy to hit unintensionally while shooting. The rail is great if you want red dot or optics, but mine has the fiber optic "firesight" front and combined with its rear is by far the best iron sighted gun I can shoot given my presbyoptia. Don't care for the mag safety and there is a goofy plastic piece at the back of the recoil spring that seems to have a short life. Mine had a great trigger out of the box. Mine has been very reliable with cheap ammo out of the box, although I had a rash of mis-fires after the screwed in "lug" that locks the upper to the lower worked loose, tightening it cured the issue.
I'm not trying to talk you out of it, but it does have its quirks. The new MkIII 22/45 also have mag safeties with decent sights and models with adjustable sights come with a Weaver mount. If your eyes are young, the Rugers are hard to beat and very mainstream, but if you are old give the M22A a carefull look as my abaility to shoot it with irons more than makes up for its quirks.
--wally.