Bests & Worsts Reviews from Amazon

I've had a Fitbit Ultra for nearly 2 years. I was an early adopter and really liked my Ultra. In those 2 years I've lost 2 (purchased 3) Ultras so when I saw info on the Fitbit site about the Flex was excited to try it as a new "better" version of my Ultra. Smaller, enclosed in a wrist band and more water resistant - sounds good! For me, personally, the reasons I wanted the Flex were to prevent losing it (the Ultra has often fallen off of my bra strap) - and to be able to sync to my iPhone when I travel instead of having to bring along the USB sync cable. I waited on back order for a long while and finally got my Flex on Monday May 20th. I charged it fully and began wearing it after reading the PDF user guide I downloaded on their website. I had a pre-existing user account (and I use MFP - MyFitnessPal for calorie tracking) and transitioning to the Flex from the Ultra went smoothly. That is the end of my positive experience. What hasn't gone smoothly is the device itself. On day one it shut itself off (no lights, no tracking) at least 3 times. Each time the only way to get it to work again was to put it in the USB charging cable. The device continues to have these issues (failing to track my sleep, because it shut off sometime in the night, shutting off part way through the day 2 or 3 times per day, being unreliable as a wake-up vibrating alarm...because it shut off again for no reason) - and so I contacted Fitbit support via their website/email after 2 days. (Wednesday morning, May 22nd first thing) I didn't get an answer until Saturday May 25th - and when I did it was a generic list of things to try. On the off chance that resetting the Flex by putting a paperclip in the hole on the bottom of the USB charger would actually fix this issue I DID follow the instructions..and then it turned itself off again, same day. (It happened shortly after 10,000 steps. It vibrated to say I reached my goal..and then shut itself off and failed to track anything more...until I noticed 2 hours later that it wasn't lighting up at all.) Honestly, I expected Fitbit support to be more responsive. I expected a response in less than 4 days. I am thoroughly disappointed that it hasn't worked, and hasn't been reliable. My Ultra was a great tracker - but this Flex has been a giant disappointment. Three other things to be aware of: 1. While the Fitbit Ultra has an altimeter - and can track when you do stairs-the Flex does not. So, if you have an Ultra and like that it tracks when you go up steps -- you will LOSE that capability with a Flex. 2. I use a desk treadmill during my workday. My Ultra could accurately count my treadmill steps even with my hands on the keyboard--but not the Flex. If you use a treadmill desk or push a stroller frequently as you walk (keeping your arms somewhat immobile) you will not get a reliable step count from a Flex. 3. My step counts with the Flex were dramatically lower and then strangely higher some days--it was all over the place. My steps with my Ultra were a lot more consistent day to day--so this leaves me thinking the Flex is not reliable (even when it was actually working--which wasn't all the time for me!). Based on all the other positive reviews I have to think that I just got a lemon--a non-working Flex. I don't see any other reviewers complaining about the Flex shutting itself off..so I guess my Flex must have a manufacturing defect. That said, the Fitbit support folks didn't respond in a timely manner to helping me with this lemon...so I'm returning it to Amazon and not planning to use Fitbit products in the future. In short - I'm deeply disappointed in the Flex and cannot recommend it.