I actually just purchased some MP 57's today with the X5.5 shafts, so hopefully I like them. I've been playing standard clubs off the rack, Titleist 990 with DGS300 shafts. My 57's are 1" long, 1* up. I was amazed at the difference in being fitted and what I've been swinging, hopefully that handicap comes down.
I've been confused when purchasing regarding shafts. I wanted a little lighter club, as my tempo is pretty smooth, and wanted a little higher flight since I've typically been able to play a punch when needed, and fairly high ball flight already, and I don't like the feel of the current shafts I use.