- RHR is a little fiddly. A lot of times it is up to 5 beats on the high side bc it isn't kicking on at the lowest hr part of the day - the hour before wakeup for me. I would hope Garmin will be fiddling with the algorithm to fix this. Otherwise, its pretty darn close to what I measure with my finger and a second hand.
- Sometimes RHR freaks out, looking like a seismograph when I'm sitting at my desk during the day. This is a temporary issue that doesn't seem to be resolved by restarts, reconnects, etc. It's happened two or three times over the last several months with both the VHR and 235, so I suspect it is an issue with the Elevate module. (Note: Garmin just updated the firmware for the 235 which "addressed issue which can cause wrist heart rate to remain on a fixed value." Not sure whether they've done it for the VHR, but they clearly know it exists, and that its a sensor issue.)
- Intensity Minutes are useless. A crapshoot as to whether you will be counted or not. Arm movement seems to help, but doesn't guarantee a brisk walk will be counted. Bike riding was more missing than hit.
- Steps are also pretty useless. A wide variation in what's measured - a staircase "up" can show 2 floors, the same one down shows "3".
- Often, there will be a spike at the beginning of the workout that resolves on its own, or if you adjust the placement on your wrist. Tightening one notch past "normal" comfortable tension definitely improves activity HR monitoring during activities.
The HR issues are pretty similar to what I'm seeing with the Garmin 235. Although they can be annoying, it still works more than good enough for me both in terms of RHR and exercise HR. And I'm convinced Garmin will work out the kinks if you have some patience - its their MO with other firmwares/devices.
Some non-HR issues:
- I hate the touchscreen. It activates the backlight at inopportune times. It messes with HR broadcasting. There should be a way to by-pass by allowing navigation with the side button.
- I found the quality of the backlight to be second rate. The lighting was not uniform - it is a minor criticism, but is exactly the kind of build issue that annoyed me on the Vivosmart original (collected a lot of dirt) and the Vivosmart original (dead LEDs). I guess Garmin views the sub $200 device line as semi-disposable... I don't think most people think like me -- that a device is only good for one product cycle. If they want to build this brand to be stronger, they need to address hardware issues on fitness bands in the way they have upped their game on mobile software.
Ray Maker covers some of these issues as well in his in-depth VHR review: http://www.dcrainmaker.com/2016/01/garmin-vivosmarthr-review.html