I've compared the SR22 and MP22 before purchase.. went with MP22 for few reasons..
- SR22, while very nicely built, felt very small and "toyish"
- LGS showed me MP22 along with MP 9mm side by side. Sizes are 95% identical. I believe MP 9mm has changeable backgrip, 22 does not.
- MP22 just feels really good in your hand like a "full sized" semi-auto.
There is a post somewhere where I go into extensive review of mp22. But it's a nice accurate shooter that's extremely fun to shoot. GL