Pro: Light, small and easy to carry for outdoor activities. Makes a great snake and varmint gun for fishing and the like, although an S&W Airweight has the same light and small factor and might be better for bigger "snakes." The single action trigger is fairly good. Mine is fun to shoot and I enjoy it. It's hard to find many parts on the gun that will rust. Mine has no problems with ammo other than feeding Aguila and all my .22 semi-autos have a problem with that brand.
Con: The small size, light weight and short barrel make the pistol difficult to shoot accurately. They will find every shooting flaw you have. The sights are rather poor for fine adjustments. The slide is zinc alloy and can be chewed up by the trigger bar ears. At 600 rounds mine was leaving slide shavings in the pistol. That went away when I polished the trigger bar ears. I consider a complete disassembly and polishing a must for longevity of the pistol. The "fixes" are found in the P22 Bible (Rimfire Central). The older (up until about a year ago) pistols have a lousy extractor. Casings tend to pop straight up or back into your face and down your shirt. The newer ones have an improved extractor. Older model magazines can have feeding problems. This has been fixed with the newer models.
About the only pistols in the P22 size are the Beretta Bobcat and the Taurus PT22. They probably have better materials of construction than the P22, but I haven't fired one of those enough to form a "better", "worse" or "same" opinion.
A fairly high percentage of P22 owners seem to be fanatical about them. I'm not sure if that's despite a number of shortcomings or because of them. Mine is fun to shoot. When I work hard and everything clicks I can shoot it fairly accurately, but it is by no means a target pistol. Currently the P22 prices around Richmond are $349 or higher. For that price, I can get a Buck Mark, Ruger or S&W 22A. All are larger but they are well ahead of the P22 in reliability, construction and accuracy. 22A's can be found for at least $100 less.