I bought one yesterday after driving myself crazy reading reviews. So far it's okay- but I haven't even been to the gym with it yet. From my reviews, it seems like all of the trackers have some flaws. None of them are perfectly accurate. The Shine is the most comfortable for me to wear- I wanted a wristband, and I have very small wrists. I don't even notice it. I like that a clock feature is there, although like others have said, it takes like 3-4 seconds to see what time it is, and requires some mental gymnastics. It tracked sleep but I don't know what for- I already know that I don't sleep well because I'm up and down with a 5 year old going through a scared of the dark phase! I swim once in awhile, so I'll use that feature. However I also use the stairmaster a lot, so I don't know if it'll track that. Maybe if I put it on my foot. It would be really cool if the Shine starts syncing with other food apps like MFP. Per their facebook page, it is in the works. I'm tempted to hang onto mine for awhile before deciding to return it- the gal at the Apple store where I bought it said Apple will return it after months of use. She also said their staff use the Shine almost exclusively. It was $120 at Apple, I may return it and get the cheaper one from Best Buy too.
Just wanted to update that I just returned mine. It worked fine the first day, but the second day it intermittantly stopped working. I kept tapping it and just one light would turn on, and no time. I plan on saving my money and getting a good heartrate monitor. It did track sleep the first night, but not the second night (again, the tapping seemed to be glitching so I couldn't "tag" sleep). When I returned it at the Apple Store the employee was wearing one herself, she said she hasn't had any problems with hers, but she had seen some returns lately.
I'm very happy with mine so far, though I have only had it for a week or so. It is a bit buggy with getting the display (sometimes the two taps doesn't register to display your progress.) But for me, the data on the iphone app is far more interesting and helpful than what the shine displays anyway -- and I always have my phone on me -- so I don't mind that I can't always find out whether I'm 40 vs. 50% to my goal. I can always look at my phone.
It's SO much nicer looking and less embarrassing to wear than the other ones. I just cannot envision a time when I'm publicly wearing a Jawbone Up, for example. My main goal is to have a visual reminder and motivator to get more activity in on a daily basis -- especially on days when I don't go to the gym. I'm happy with it, and I imagine they will continue to make improvements. Apparently the latest version of the firmware and app added a lot of functionality.
Lastly, it's the only one I found that tracks cycling well, which is most of my non-gym activity.