"it's significantly more accurate than any other fitness tracker's"

More precisely, according to one study, compared to other devices including Fitbit's 2014 model, Surge, Apple Watch in workout mode was found to be more accurate.

You know Apple Watch was in workout mode for the study because outside of workout mode Apple Watch only measures heart rate when you're still, according to https://support.apple.com/en-us/HT204666 ... note that in workout mode Apple Watch battery life is "up to 8 hours" according to https://www.apple.com/watch/battery.html

The study did not examine more recent Fitbit models (Blaze, Charge 2, Alta HR) and did not examine Apple Watch outside of workout mode.

Disclaimer: I work for Fitbit but don't speak for Fitbit.

I'd also take the results of that study with a pinch of salt - even if it is "the best" among the very small number of watches tested, most athlete focused reviews of the Apple Watch's HR performance show it being noticeably worse than a dedicated Bluetooth or ANT+ chest strap monitor, like the kind many cyclists and runners use. Speaking from my own experiences, the collection of ANT+ HR straps I've amassed over the years all work better than my Apple Watch's optical system does - way less odd outlier values etc. This seems to be true of most wrist worn optical heart rate measurement systems. If you are really keen to use heart rate as a training tool, the Apple Watch arguably shouldn't be your first choice.

"What’s notable to start with is that it took almost 2 minutes after pressing the start button for the Apple Watch to decide on a heart rate. At which point that heart rate was incorrect by 40 beats. It wasn’t until 7 minutes into the run that it agreed with everyone else."

https://www.dcrainmaker.com/2017/02/apple-watch-series2-nike...

I actually ended up with the Pebble Time also, and excitedly pre-ordered the Time 2. I would have been willing to pay so much more for it, and I wish they'd just told their backers that either everyone could pay an extra $100 or it was gonna go bust. I imagine I'm not the only one who would pay Apple Watch prices for a Pebble Time 2.

I have no idea what I'll get when my current Pebble bites the dust. I'm not sure which is more likely: that Apple offer a watch with more than a couple days battery life, or that Fitbit actually integrate the Pebble tech (and reliability) into their devices. Sigh.

I was in the same boat - I ended up replacing my third Pebble with a Garmin Vivoactive HR. It seems to have fulfilled all of my old requirements (notifications, good battery, custom watch faces, 3rd party apps), and then added a few I didn't know I wanted (GPS fitness tracking, Heart Rate Monitor).

I've had an original Apple Watch for three years and have never needed more battery life. You charge it when you sleep. It charges super fast so if your forget you can charge it while taking a shower. When I forgot to charge it once, it still lasted all the second day too.

And it has an excellent heart rate monitor.