I have the MDC Ultimates (flex joints plus rotated eye) and love them. I was recently considering going back to a regular iron w/ just the rotated eye (MDC just came out with a sport version like this with an aluminum footrest for lighter, prettier stirrup) but I was paying attention to how I ride the other day and I DO use the while joint posting. I can see it flexing while in the saddle.
I bought the MDCs several years ago because I had knee issues in the saddle (I had stopped playing soccer because my knees got bad - age 27) Now 35, I ride pain free. I've never used the knockoffs so I can't compare. I DO like my MDCs which I ride with the 90 degree eye as well and I never run up my stirrups anymore.
Oh and I also wonder how much cushion I'm getting from the white rubber foot pad that came w/ my MDCs give as opposed to the new sport design which is a solid aluminum. That could be a factor in your buying process, a solid metal or rubber pad.
Last edited by shadowanne; 07-21-2010 at 06:42 PM.