I bought a PSA 5.7 just because. There are some interesting tests out there on the www. Penetration and expansion tests often show early upset and significant wound channels with shallow penetration. Many of the tests also show some inconsistency. Seems controllablity, capacity and soft armor capability are the chief selling points. I'll add another. 150 rounds of 5.7 weighs about the same and takes up about the same space as 50 rounds of 9mm. I really wouldn't want to take a hit from a 5.7. I'd imagine a center mass hit with it will suck the will to fight out of most people.
