I have owned a Jawbone UP24 which I think has now been superseded by Jawbone Up2.
The main reason I bought the jawbone was because it came in orange lol, its my fav colour. But it has plenty of cool features.
Idle Alert - so when you have been sitting around doing nothing for too long, it reminds you to get off your lazy ass!
Step tracking - It counts how many steps you have done each day, you can set goals and the smartphone app will tally it all up and report back how much you have done.
Sleep tracking - It works out how much sleep you have had in total, deep sleep and light sleep and you can see over a period of time how good or bad you are doing ( This feature was one of the main reasons I gave up shift work!)
Food tracking via the app- I never bothered with this, but my brother and friends logged all their food and found it really interesting to see how much they were actually eating.
The app lets you log work outs you have done and the type you have done, and estimated calories burned etc, all very good and if your friends have it too you can be part of the same team and motivate each other etc!
The Jawbone app links to a lot of other apps too, like Run Keeper for example
The main issue with the Jawbone band, which may have been sorted out with the newer versions was that, they were pretty fragile and a bit unreliable at times. My friends lasted about 6 months on average, a year tops. Mine after a year started acting up and the button on the band stopped working, but I could still use it via the app. Sometimes it would just lose all power even when it was nearly full, and then would require a full recharge again (this happened about 5 times in the near 2 years I had it).
Also battery life was never 14 days, I got a week at best
After the jawbone, I decided on a Xiaomi Mi Fitband
This is super cheap like $20 all in, it has a good app, but it doesn't do a lot of the fancy stuff that the Jawbone does.
So the key features, it can be used to unlock your mobile phone too, depending on what version of android etc you are using. It is pretty well built and the battery lasts 30 days...a realistic 30 days! I have used it for 30 days between charging, that is pretty epic!
There are plenty of fake bands about so just be careful when buying. For the price its a total bargain as far as I am concerned!
You can look back over the last week/month etc and see how much you've done on average, also there are other fitness bands, so find one you like at the right price point to get you going.
These are just 2 I have used so I can comment on.
The app isn't as invasive as the Jawbone. The Jawbone app would always give you updates and tell you , that you were being lazy etc and tell you at around midday how much you had or hadn't done. The App for the Mi Fitband doesn't do any of that, you have to go into it to get an idea of where you're at, and the app doesn't link to anything else apart from Google Fit App, which is OK but nothing special. But then again look at how much you are paying for it!