After giving up waiting for the red Jawbone UP , I bought my wife and I each an Onyx Jawbone UP 2 months ago. It matches the colors of our Pebbles better anyway. After wearing it almost all the time — showers, sleep, exercise, doing household chores, walking round and bringing it with me on a short getaway. Here's my thoughts.
It's great. It's water-resistant but not waterproof, so you can't wear it and track your swims. I swim regularly and it boggles my mind that Jawbone don't include swimming in their list of activity types which you can manually enter.
Not only does the UP track sleep, there's actually 2 types of alarm 1) Smart Sleep Alarms, you set a time — it can be different for each day and 2) Power Nap alarms, you set a nap length. In both cases, it wakes you up when you are in light sleep.
One of the main reasons why I bought the UP was to track overnight sleep as well as use it as a power nap alarm. It does both wonderfully. The vibrating alarm also wakes me up without waking my wife. Just yesterday, it tells me I had 73% deep sleep out of the whole night which is the top 10% of UP users. How cool is that! I also found that I can function well with 5 to 6.5 hours sleep as I get a decent amount of deep sleep most nights.
This is the version two of Jawbone UP (version 1 was the one where they refunded most/all purchases and suspended sales due to poor build quality). Anecdotally, the quality still can be very much improved — my sleep indicator lights no longer work. Jawbone has been kind enough to mail me a replacement though.
One of the reasons why I bought the UP was because it has a nice looking iPhone app with pretty charts. After a few weeks of use, however, it is obvious the food tracking section of the app is poorly implemented. Search is terrible, the most obviously relevant items don't always come up at the top of the search results. Searching for food that you previously logged to log them again is hard because of the poor search so you sometimes have to rely on scrolling through pages of photos of food that you logged. The most immediate way to improve food tracking functionality is to make search better.
Some users compare the UP to other devices and complain that the UP doesn't support wireless synchronisation. I don't mind having to remove the cap and plug it into my iPhone audio jack to manually sync. In fact, I do it several times a day.
There are still a few immediate things UP and its app that can be improved on. It would be good if it is waterproof and can be used to track swims. I eat regularly with my wife and it would be great if we can share custom food items that we have created with friends so we don't have to do it twice.
I'd buy it again.
 Recently, I've noticed that they no longer have the red UP listed “coming soon” anymore. They have removed it totally. I wonder why.
Update 27-Feb-2013: There's now an orange version of the Jawbone UP which Jawbone will make a donation of $20 to the Alliance for a Healthier Generation for every Orange UP band sold.
Like this post? Follow me @hboon on Twitter.