Interfaces with radar/light unit, easy on/off mounting (came with numerous mounting options). Good battery life. Like the feature ability to track fellow riders over busy courses (e.g RAGBRAI type events).
I was updating my old Garmin Edge 530 which served me faithfully for 6 years or so. I don't replace gear that often so this was a big change for me. My first impressions after 200 miles or so indoors and out. The unboxing process was seamless; I unboxed it and synched it using house wi-fi. Everything from my old unit worked seamlessly and the process was fast. Initially I noticed my phone would interfere with the Wahoo Kickr core signal. Solution was to connect phone last. Same thing happened using a Garmin Varia. I just needed to connect ap on phone after getting 840 set up. Otherwise system is a great upgrade. I actually was on the fence about touchscreen but after using it for a couple months I've gotten used to it and love it. Overall great experience and I'm happy I didn't spring for the extra solar charging unit.
The arm band is incredibly comfortable and most of the time I forget I'm wearing it. I love the fact that its rechargeable so no batteries to change. You can get several different color armbands which are interchangable if you want a bright color. I never have a problem connecting to any device or trainer.
Midwest weather had a freak warm day last week (72 degrees in March!) so we ventured a short leg-stretching ride. This Varia 820 is an upgrade for me from the 515, and it IS as-advertised. I use it with an Edge 1040 and the new vehicle icons and wider display are far more useful, particularly in the kind of riding I do... out in the country, where a car/pickup can sneak up on you really really fast. The ONLY complaint I have so far has to do with the same, ongoing problem: the volume of the notification chime. Windy rides, at pace, you just can't hear the notification. You just have to get into the habit of the quick glance as part of your awareness "rotation." These will be gifts for my grandson and his father as well.
See the online YouTube reviews from Llama and DM for really good tech evaluations.
