I ride in the MDC ‘S’ Classic - http://mdcstirrups.com/s_classic.html
I have ankle and knee problems from years of overextending in flexible stirrups. I like that the wide footbed really stabilizes my entire leg (and therefore position) and keeps my them from turning into overextended, weak mush. I also prefer a heavy stirrup to a lightweight stirrup so that they’re easier to get back should I lose them. The swivelled top is also a neat feature - I find that I never noticed the stirrup leather before, but now when I borrow a saddle I can’t ignore them there, and it also makes it easier to get the stirrup back.
I catch ride in all three rings, and I love that they are are super traditional looking, while actually feeling very different than a traditional iron. I see very few younger hunter/eq riders in traditional stirrups now on the As.
We also have some Royal Riders, JINs, Lorenzinis etc in our barn that are well-loved by their riders. When I was picking out new stirrups, the other riders allowed me to borrow theirs and figure out what worked best for me. I found that the JINs are a less traditional look, but very similar feel to the MDC (minus the swivel top). The Lorenzinis were no good for me because I need something hunter/eq approved, and I thought that the silver RR were pretty ugly and also caused my knee pain. Hands down, the MDCs rode the best and also looked the best (to me).