I was gifted with a pair of the jointed ones and find them comfortable, but not that much different than regular irons for dressage. For jumping, I find they are a LOT more comfortable. Would like a pair of the MDCs, but the $$$ ain't there, so I'll just keep using what I've got.
I rode in the Bow Balance for months, thinking they were fantastic. Had knee surgery, was out 4 months. Got back to riding and even after months thought my problem with stability was my bad knee, lack of strength. I happened to ride in my husband's saddle one day, which had regular irons, and could not believe how much more stable my leg felt. I switched back to fillis, but I did get the cheese grater pads because I loved them on the BB. I sold my BB on ebay on the first day I listed them, for about 75% of what I paid for them.