I went through this process a month or so ago coming from an Edge 305.
That was a great unit but I wanted mapping. I I looked long and hard at the Bryton before going with the painfully expensive 810. What tipped it for me was that it’s a Garmin, with a bit of work pretty much any map can go on it, the virtual partner feature, and the phone connectivity and ‘watch my ride’ feature. Now I’ve been using it through some terrible weather, it hasn’t skipped a beat. The touchscreen is the real surprise. I thought it’d be a compromise, but even with thermal waterproof gloves on it works like a dream. The phone-based upload is also a great feature. As soon as you hit save during or at the end of a ride, it’s uploaded (in around 5 seconds) to Garmin Connects website, and Facebook and Twitter if you so wish too. Really excellent stuff.