I probably already said this in this thread, but Garmin responded positively to Wahoo having much better devices. So if your garmin experience is defined by something built before the 1030 or 830, it's not a good basis for decision making. I understand it though, there have been many occasions where I swore I would never buy another garmin device because of my 800. And so I was somewhat reluctant to buy my 830. OTOH, about that time some randonneurs I knew were having problems with their wahoo devices and some of them got the runaround from wahoo in ways that I didn't think I would tolerate too well. At the same time, people were reporting good luck on 1200k's with the 830.
Even the 820 era devices weren't that great for distance rides and had some problems people had been complaining about since the 800. I know that long distance really isn't driving a lot of business to them, but I never saw why they would make a device that was likely to crash before it hit 200 miles in a day. Nowadays, long distance has gotten pretty popular for racing, and even if people don't do it themselves, they would find out if some well-known person had a problem with their gps. But an 830 is unlikely to have any problems on a long distance ride.