I have an AA kit for my G17 and let me tell you that it has paid for itself several times over, not only financially (by being able to use .22LR in my my 9mm) but by the fact that I now shoot 9mm so much better than I ever thought possible.
I used to have a ridiculous flinch (I'm kind of adverse to recoil... yes, even 9mm) but now, no longer. Shooting literally thousands of .22 rounds out of the same platform that I shoot 9mm out of was a huge help. I went from shooting around 12" at 25 yards to about 6". Yeah, the fact that you have to buy a spare mag (or two) kinda sucks but it's worth it.
I can also speak for the Mosquito as I have previously owned one of them as well. If you have small hands, they're ok... but they do tend to be very picky on ammo. If you find the right ammo, they are a dream, If you can't find it, they are a nightmare.