A big part in this comes from the fact that most people take off the watch when they sleep to charge it, making it useless for sleep tracking.

On the series 2 it's not an issue at all.

I believe David Smith, the developer of Sleep++, said that on the original Apple Watch he wore it all day and all night and simply charged it in the morning and in the evening while taking a shower or doing the dishes or something like that. It doesn't take that long to charge the thing up all the way, so two short charges while you're doing other things would be enough to top it off.

On the series 2 the battery life is so good that just charging it while you take a shower in the morning is probably more than enough.

This is what I do. I charge the watch in the morning when I get to my office and wear it all day (and to sleep, for the silent alarm feature).

With gen 2 Apple Watch that shouldn't be necessary - I wear mine diligently and interact with it frequently yet the battery never gets below 70% at the end of the day, often only getting down to 90%, and the charge time is quite rapid. Stick it on the charger when going for a shower or some other short routine and you should have it back to fully charged when you're done.

Get the Milanese Loop band and it'll be even less of a pain because you can quickly put the watch on and take it off because it's magnetic. A lot easier than a buckle or pin fastener.

For anyone interested the sleep tracking app I use, Sleep Watch, automatically figures out when you're sleeping and awake so you don't have to manually initiate the app. I guess it interprets movement data from the accelerometer and can tell the difference between slight movements in a sleeping state and respite during wakeful periods.

I find that the battery stays pretty high (around 80%) if I don't exercise with it. If I start any workouts, however, and the battery dips down to ~50% by the end of the day. Nothing that a quick top-off during the day wouldn't fix, but it's still far from the Pebble's week long battery life.

Does the Pebble have an integrated GPS or does it rely on a phone with GPS?

I wonder if the form of exercise also has an impact. I'm averaging 12.5km walking/running per day or 7.5+ miles but my primary form of exercise is weight lifting which wouldn't be very taxing on the watch at all. On the other hand someone doing jumping jacks and various other flail-y cardio exercises might be triggering the screen to turn on an off and making the accelerometer work for its supper. Rapid changes in air-pressure might also be triggering the mic/DSP to listen for speech.