I ride a 157 and weigh 180. I find the proto has no speed stability for anything outside the park. It's great when you want skate the mountain going from hit to hit when the hits are close to each other, however if there is a long stretch between hits and you want to put the hammer down the proto quickly turns into a chatter box.
I totally disagree. I'm amazed that this board can carve as well as it can. Deep trenches on black trails that were not perfectly groomed, and I'm 200 lbs on a 157. You will get chatter with all but the stiffest boards if you want to straight-line double blacks all day.
I bought a T. Rice for shredding fast, but the Proto handles itself so well I find myself only grabbing the T. Rice when it's a powder day cause it's 5 cm longer...