I have a Fitbit Flex. It worked pretty well for about six months until I got a nice rash where the band clasped together. It visibly lasted for a couple of months. I tried wearing it after a long layoff later, but mentally I just couldn't. Thankfully I don't have a big scar there like I thought I would, even though on the inside of your wrist is hardly a huge deal. But that thing hurt for a few weeks.
Mine wasn't part of the recall, so I pretty much just have it. Fitbit doesn't have any third-party bands or others made from different material. So I've been using my iPhone to track steps, and it does a pretty good job.
Fitness tracking is one of the things I'd like to get out of the watch. I've been dealing with tendonitis in my Achilles for about five years, which adds to the fun of being more active. Recently I think I finally got it turned around with some good inserts (like doctor-ordered $180 good). With my phone tucked away in a pocket, I'm not constantly reminded of my progress or lack thereof. But with the "BUZZ, move your ass!" feature of the watch, I figure that may help some.
I wish it had more sensors like some of those I read about recently that are planned for future models, like glucose, oxygen, even blood pressure (???). If one of these could constantly monitor all sorts of stuff like that and then store it in Health, I think it could help a lot of doctors get better information on your health. I use a sleep tracker with my phone, and I think it helps me see how little or much I sleep and whether I'm "restless" a lot. I just wish the app was a little easier to turn on and use when taking a quick nap.