I have a pair of blue metallic ones and they required a little experimentation before they worked for me. I need to wear them with insoles and invisible socks to fill up the extra room and up the comfort level. I also had to relace them to get the fit right — at first they seemed like they were going to slip off my heels. I need to do a special lacing technique and tie them fairly tight for them to be secure, but once I got that right, I’ve enjoyed wearing them. They are a little on the heavy side, but not so much to be a deal-breaker.
I remember trying on another pair a couple of years ago that didn’t work for me at all, so I think the fit and comfort varies quite a bit across styles.