I have used one in the past because I thought I needed more. I don't. I just maxed out on size very young and just considered myself average because of it. I was never in the business of up and close comparisons to confirm it either. I do agree that if some males don't have that fully engorged erection it would definitely provide more size/girth temporary or until after repeated uses the maximized filling of the tissue with blood becomes a normal mechanical biological function.
It is true in your observance that its an instant way to get an erecton and decrease recovery time as it does draw/fill blood back into the shaft of the penis. It also helps males to hold an erection longer as the ability to having the device maintain an erection for long periods of time becomes adaptable to you being able to do the same. I might need to go whip mines out from the box again.