I really hesitated between giving this four stars and give. On the one hand, it isn't as app capable as Android Wear watches. On the other hand, it carries out its intended purposes extremely well. Ultimately, my choice hinged on recognizing that adding app functionality could necessarily take away from the watch in it's current form. It's not fair to compare it to the specs of a watch two or three years into the future.
I got the vivoactive hr to replace my Fitbit Surge. I'd decided I wanted a bigger screen. The Fitbit's band was wearing out and there was no easy way to get a replacement (if you're under warranty, the likely response from Fitbit is to replace the watch altogether). I still wanted all the Fitbit features, all day heart rate tracking, built in GPS, 3-4 day battery life, sleep tracking, workout tracking, and activity prompting. I also wanted something a bit more exciting screen-wise.
Not only did the HR meet all my requirements, it exceeded them. The Fitbit did well tracking heart rate so long as it was below 100bpm. This watch seems to have much better response across the entire range. The app lets you drill down into a lot more detail than the Fitbit though it is not as well polished. Still, I prefer Garmin's approach to sleep and workout data, it seems to capture and show parameters that fit more into how I'd like to look at things. The activity prompts seem to work better - I'm more likely to respond now than with the Surge.
I also like the ancillary features, being able to find my phone, detailed notifications (notifications and audio control just never seemed to work right on the Fitbit). While I've noticed a lot of firmware updates since I got the watch, it doesn't regularly get into a state where I had to try rebooting watch, phone, or both to get things working again. In fact, this only happened once, after a firmware update the night I first used the watch (it's been over a month) where with the Fitbit, this was almost a weekly occurrence.
I like the additional detail with my workouts, HR, HR zone, calories, time, all easily viewable. The Fitbit shows most of the same information, but you'd need to swipe through to see it. Taking them on a run side by side and looking at the plotted map of my run afterwards, the Garmin seems to have better GPS tracking (I'd waited until both watches reported a lock). Also, the Garmin consistently achieves GPS lock faster than the Fitbit did by a huge margin.
The Garmin's charger is also nicely designed. I feel inductive charging would have been a better feature or a standard connector like USB, however the charger is designed for secure attachment to the watch. Also an improvement over some of the competitors.
Battery life is awesome. I consistently have been getting 5-7 days of life (if we keep GPS sessions down to once a week). This includes three hour long workout sessions each week (with the increased heart rate tracking). The Fitbit under the same circumstances would last 3-4 days. Due to the screen settings, the watch is a lot quieter in the dark which is nice when trying to get to sleep.
The price, size, battery life, color screen, and feature set make this a pretty compelling watch if you're looking for a casual fitness tracker. As of now, it's my top recommendation.