I rocked one for multiple years. When it finally died a few months ago, I had a funeral.
I had a Pebble 2 HR. And yes, the HR means it had heart rate monitoring.
The step counter wasn't bad. It was off by < 10% compared to some of the other things I've used. The heart rate monitoring wasn't bad; within about 5% of a chest-strap-mounted heart rate sensor. The sleep tracking was quite good.
It had a smart alarm. I could give it a 30-minute window in the morning and it would wake me up, as early as possible within that window, when I was in a light-sleep state. Trying to wake up, when in a deep-sleep state, leaves me groggy as hell; I never woke up groggy with this. I could make any alarm a smart alarm, including different times for different days of the week (getting up for work on weekdays vs getting up Sunday morning for church vs no alarm on Saturday morning). I could set / disable / alter these alarms on the watch itself, instead of needing to use the app. If I was off work tomorrow, I could disable the wake-up alarms for the next morning on the watch itself.
If you were willing to leave the Bluetooth on all the time (which ran the battery down), you could use it to:
- control music, playing on your phone
- see who was calling
- see incoming text messages
- send one of a handful of canned responses
etc. If I left the BT off most of the time, I could go 7 - 10 days on a charge. If I left it on all the time, two days tops.
The app synced with Google Calendar, such that appointments with notifications on them would trigger the vibration alarm on the Pebble. I could be eating lunch and ... oh, crap, I forgot about that meeting. I was rarely ever late for an appointment or meeting because the watch didn't have to be actively synced with my phone, at the moment, to know about appointments. It would hold a couple days' worth of appointments; I made a point to sync it every day or so, such that it stayed up-to-date on what was upcoming and sync'ed my sleep tracking and step count off to the app.
When my phone would no longer work with it (updated to newer version of Android), I had it sync with my tablet (still running an older version of Android). Sounds like the new app would let me use it with my newer phone, if I still had a Pebble.
If I woke up late at night and needed to navigate to the bathroom, I could tap the watch and it would illuminate just enough that my adjusted-to-the-dark eyes could see obstacles and I wouldn't bump into stuff. It was pretty faint; I could do this without waking up my beloved.
There were a variety of watch faces to choose from; I settled on one with large digits that was very easy to read at a glance. There were also other apps you could load. I kept a countdown timer app. I'd put laundry in the dryer, start a countdown timer, put laundry in the washer, start a countdown timer, put something in the oven, start a countdown timer, etc. and it would silently notify me when each of these expired. I couldn't begin to count how many loads of laundry I dealt with, how many loaves of bread I proofed and baked, over the years, with this thing silently letting me know when to get up and deal with something.
There's no way for a smartphone to do sleep tracking or smart alarm things; only something wearable is going to know what sleep state you're in. A smartphone can do everything else, assuming you carry it all the time.
Still looking for a smartwatch which can duplicate ALL of that. I'm wearing a cheaper device from Withings, at the moment; it tracks sleep and step count and can have one smart alarm per week (it wakes me up for work, on weekdays), but that's it. When I find something which can do the smart alarms, hold multiple days' of appointments and run various apps, without needing to be BT tethered all the time and without needing to be charged every day, I'll probably plunk for it. That seems to be a pretty tall order; I was very spoiled by my Pebble. It's gotten really hard to find Pebble 2 HRs out there; they don't last forever and they're in very high demand, so anyone parting with one either has serious issues with it OR wants a small fortune for it.