I own a P226 22 Classic as well as the others you mentioned, the CZ Kadet, Beretta 87 Gold Standard and Kimber Rimfire Target.
The SIG is the least accurate of the four and the slide and frame finishes are mismatched, but, it's still a decent 22 at any rate.
The SIG is also convertable to centerfire and I have X-Change kits making it 9mm, .357 SIG and .40 S&W as well. All in the same case.
NRA Endowment Member