A faster arrow of the same weight has more momentum therefore more penetration. Speed helps penetration as long as other things aren't sacrificed.

OK as to why I shoot the bow I do....well I currently do not even have a bow, I sold my old one which was a PSE Nova, and the reason I bought it was that i felt it was the best buy for what I could afford at the time.

When I purchase my new bow, the criteria I will use are quietness, forgiveness, the way it feels in my hand, and can't help it, but looks too. Price is also a factor, I'm on a mid range budget.