Before I bought my Onza, I shot several bows, including a couple that had 350+ IBO speeds... and my shoulder was PISSED at me. I would have to get a 60 pound version just to shoot comfortably. (Which is no big deal, my next bow will probably be a 60# anyways)
Not to mention that part of getting those speeds is a lower brace height, which I could see being a problem hunting with a jacket and gloves; I'd be smacking my sleeve all the time! (ie; Mathews MR5 is 360+ IBO, 5" BH; PSE Omen Pro is 360+ IBO, 5.5" BH) They may be fast, but I have a feeling they'd be awefully unforgiving!