I have an A22 and 2 x ruger 10/22's (takedown and one in a troy chassis) The pros for the A22 is that it can run the 25 round mags as previously stated, and also that you can remove the bolt without having to remove the whole receiver from the stock. That being said the plastic cap can be a PITA to remove and place back on sometimes as you have to line the pin back up. Best reference would be kinda like how the cover removes from an AK or a type 81 where you have to push the button in.
Another issue with mine is that I've haven't seen with the rugers (that have a much higher round count) is that on the A22 is that a noticable dent on the chamber face has become obvious from the firing pin striking it..... might just be my gun. It should be noted that the Rugers have also been "dryfired" much more then the A22 ever had been. Dry firing isn't the best for any rimfire, but the A22 doesn't seem to like it very much.
I will also make a point of saying that I do not dry fire my guns on purpose and that sometimes i lose count of the rounds left in the magazine and pull the trigger on an empty chamber sometimes. My rugers have had thousands of rounds through each and neither show any chamber or firing pin marks. Just something to keep in mind.
I had one issue with the ruger not ejecting cases and stovepiping - I just needed to file / smooth the extractor claw and that solved that issue.
If I had to choose I would pick up a Ruger 10/22.... it is a more solid gun then the A22 in my opinion.