It's been my experience that the vast majority of issues relating to Edge units, particularly the 705, 800, 810 and up, could be solved by good housekeeping practices. I'm amazed at the number of friends I see who let tens of .TCX history files crowd their Garmin and then have problems. Whereas I keep my 705 tidy in that area and have almost zero problems.
Now, you could say that shouldn't happen and I'd agree with you. But if you've got a device that does 90 percent of what you want reliably and the other 10 percent of aggravation/dysfunction could be solved largely by different behavior, I'd pick the latter approach.
But I also recognize that different people have different issues. For me, the "bug" with them has been their HRM straps are crap and I've had the basic ones, the deluxe, etc. and they all work pretty poorly even with electrode gel to help conduct heart rate in cool, dry conditions. To me, that shouldn't happen.