The predominent sentiment, as I understand it, is that higher cappers play cavity backs because they're more forgiving on hits that aren't spot on the sweet spot, and lower cappers play forged/blades/muscle backs whatever you want to call them because they are more workable (and those players have no problem hitting the sweet spot consistently).
As my ball striking has improved, I've started working on shot shape, and honestly, I don't have much of a problem making the ball move the way I (I am by no means claiming I hit my target consistently, most of the time I overcook my draws 15 yards left of the target). I play Callaway Razr X irons, full cavity, cast, game improvement irons. I've hit Mizuno MP-53's and Titleist Ap2's, and when I do strike them pure, I lose about 10 yards compared to my Razr X's.
My question therefore is where the benefit of blades or forged clubs lies? I can work my cavity backs and the go longer. I don't see the point in using a club that's harder to hit and shorter (for me at least).