The Jawbone app is essential to the function of the UP24, especially since there is no screen on the device. That being said, I'd much rather look at a huge, nice iPhone display than an 8-bit readout that looks like it's from a vintage digital watch. The main screen you will see (left) indicates your sleep (purple) and steps (orange) by percentage of your "daily goal" and also a total count. Below those two indicators, you will see tips on how to improve your lifestyle / health and eating habits. Most of them are actually quite useful and interesting. Behind the main screen is the one seen here on the right, which indicates the various custom settings and parameters you choose for the fitness band to alert or remind you of various things. Alarms, inactivity warning or "Idle Alert," even reminders to eat can be set here. Overall a fairly useful pair of screens to control the Jawbone UP24.
Almost everything was good about my experience with this fitness tracker. What bothers me about it? Annoying alarm functions: If I am asleep, why does it wake me up and then tell me to go to sleep? Not really in the category of "cons," it's really more of just a "quirk" or minor complaint. But a couple of times, when I went to bed earlier than the preset time I selected in the app, the UP24 would vibrate (when I was already asleep, and had put it in sleep mode) to remind me that it was "time for bed." Thanks wristband, but I already told you I was going to sleep by pressing the button for sleep mode.