Advice needed - Garmin Edge 820 + Garmin Vivoactive 3

I don't have a VA, but I do use my 820 for navigating and finding my way while mtbing. The included OSM maps show just about every trail everywhere I've ridden, and the GPS accurately puts me on them. Many are routable, meaning you can create a course, download it to the 820, and it will provide turn instructions. However, on the complex network of trails I typically ride, I don't find this useful. In general, I'd say it works well with the major caveat being the difficulty using the erratic touch screen to pan and zoom the map. At my desk, with deliberate and practiced use, I can get the touch screen to work OK. On the trails, it can be quite frustrating. Personally, I'd look for a device that works better in this regard. I considered the touch-screen-less 520+, but zooming takes many button presses descending through menus and there is no panning capability, AFAIK.

Thanks for your input Iooigi! Much appreciate it.

I take it from your words i should buy the device? Better than this perhaps only the 10xx and this one already is a bit over my short budget!

I have both VA3 and Edge 820, here are my impressions. It's only my opinion and I might be mistaken and things might change with upcoming FW but Garmin forums could not offer solutions for problems I've faced.

1) Both devices do not look like they belong to the same ecosystem. VA3 supports TrueUp, 820 doesn't. 820 can broadcast data to external screens but VA3 does not accept that.
2) VA3 sends you Move alerts while you're doing your 50 miles ride with 170 BPM and 30 kph speed and the only option to get rid of it is switching off the move alert
3) VA3 with FW 5.20 cannot broadcast HR and show current time or do anything else at the same moment.
4) It's a huge masochism to use 820 as a bike navigator since even the cheapest and crappiest android smartphone with a free navigation app does the job better.
5) 820 is quite a good indoor bike computer since cadence meter and 820's heart rate monitor are quite precise and edge 820 (not edge explore) is compatible with indoor trainers power meters. However, sometimes it loses connection with cadence and power sensors.

Probably purchasing Edge 130 might be a better choice.

...4) It's a huge masochism to use 820 as a bike navigator since even the cheapest and crappiest android smartphone with a free navigation app does the job better...

I would not disagree with this. You can use the OSM app on your smartphone with its much larger and better touch screen and download map areas so that you don't need a data connection while riding. You don't even need a cellular account as you can download the app and maps via wifi. Some are ANT+ and BTsmart capable. Smart phones are, in general, larger, less robust, and have relatively short battery life. Having bought an 820, I live with it, but with how I use it and knowing what I know now, I'd look elsewhere.

....
For this I'm thinking of buying the Edge 820 .

My plan is to use the Garmin Edge 820 as my main record device while cycling, while having the Vivoactive 3 broadcasting my HR to the 820.

Questions:
- Since i won't be using VA3 with GPS, only the HR broadcasting, will it save battery life?
- Does this technology work? Or is it plagued with problems?
- Will the Edge 820 really improve the experience of my "lone" MTB rides?

Any other comments or experiences you can share with me will be greatly appreciated.

I used my VA3 to broadcast HR to my 820 for the first 6 months of owning the VA3. Since then, I purchased a separate HRM to broadcast HR to my 820, now the VA3 is along for the ride counting Intensity minutes. I also use the HRM with my VA3 for spin class. The combination 820, VA3 and HRM work perfectly for me.