My sleep sleeve is more or less useless. The velcro doesn't stay closed, so it invariable gets caught on something, pulls open, and then, in addition to not actually tracking movement during my sleep because it isn't attached to me, I have to search for it amongst my bedding in the morning. If you look through the forums you will see that this is a fairly common issue for One users, and many of them have come up with clever solutions. The most common fix appears to be buying a sweatband for the wrist, cutting a very small slit in it, putting the One in the slit, and wearing the band with the slit side down to keep the tracker in place while sleeping. I haven't tried this myself, but I certainly would if the sleep tracking was especially important to me. As it is, I just take my One off at night and skip the sleep tracking- but that solution also renders the silent alarm useless, which sounds like a deal breaker for you. As far as the silicone holder/clip goes, mine has recently developed a crack in the plastic tip which covers the metal clip part (the part that holds it onto your clothing). Again, I saw from other forum posts that this is a really common problem, so I contacted Fitbit support and they are sending me a new clip free of charge. If your clip is breaking or malfunctioning, I'd suggest getting in touch with them before paying for a replacement.
