The 5.7 is a 22 magnum magnum. Not that there is anythign wrong with that. I love my 22wmr savage bolt gun - 1" groups at 100 yards all day with a crappy $20 scope, and clay pigeons at 200 yards all day as well. But, a box of 50 rounds costs me $10 instead of $20-30...
A buddy has a PS90, and while it is fun to shoot, it is not what I want in a gun. Then I've gotten funny in my "old" age... no more 9mms, I have a 1911 now. No more AR15, I have a FAL now. Heck, the only 22lr rifle I have is for my daughter - my rimfire is the savage 22wmr...
Personally I'm waiting for more guns in the 5.7 caliber. I think something like my Savage 93 in 5.7 would just be sweet. Or a pistol barrel for a TC Encore. Or even a full size bolt gun.