I have a pair without the spring foot pad that I really like (have a pair of HS 4-way stirrups that don't feel any different than fixed stirrups, so I didn't pay the extra amount for MDC with spring). After doing alot of Pilates, and being told over and over how important patellar tracking is (having the kneecap pointing the same direction as the 2nd and 3rd toe) I realized how difficult that is to achieve with one particular horse/saddle that I ride. The lack of stirrup leather pressure wanting to turn the foot in when using the MDC at a 90 degree angle has made me feel much free-er, all the way up to the hip.
Haven't invested in a second pair for my other horse since she is much narrower up top and that makes a big difference in the feel to me.
I didn't have any particular problem that I thought the MD stirrups would address. I frankly thought they were way overpriced. I didn't really think they would be that much better than my 4-way stirrups. Well, in a fit of craziness, I bought a pair. I LOVE THEM!!!!!!!!!!!!!! I can really feel a difference. When I ride in another saddle, I really miss them. I think they help with my position. But they are soooooooooo comfortable. I would highly recommend them. I think they are worth every penny.
I second that. I bought mine at vto's sale, and just love them. I have a bad hip, and I wasn't sure they would do anything to help, but figured it was worth a try. Much less hip pain. Who would have thought.
I have the flexible ones. They made a huge difference when I was using regular wide leather stirrup leathers; now that I have narrower, nylon lined stirrup leathers that seem a little more flexible, I don't think I need the MDCs as much. But they have been great for my ankle (old sprain never treated with PT).
I love mine, but not everyone does. I had a conversation with the owner of the company last year and according to him, people either love them or hate them - no in between. So, I would always recommend trying before buying if you can.
I love them and have them on both my jumping saddle and dressage saddle. My ankles are a big source of pain, they help to take the pressure off my knees and ankles. Occasionally when I ride in a different saddle with regular irons I can feel the difference the next day
To be honest, I don't find that they really make any difference at all, compared to your traditional, run of the mill, cheap stirrups. That said, I don't have any knee, hip, ankle pain. Maybe if I did I would notice a difference?