As the OP - I have Memory Map on a Windows PC with OS 1-50,000, OS 1-10,000 and France at 1-100 and 1-250 scale - as well as the "free" GB overall route planning maps.
Been using it since 2003 with a couple of special price upgrades to a version only a couple of years old. [I did have quite a few "evaluation copies" of the 1-25.000 maps - but they don't work with the latest core software]
I like using it as : a) on the PC you can hop easily from 50,000 to 10,000 scale b) you can scroll across the map area faster than any of the online OS offerings that I've seen c) saving routes to my own PC is simple (as is then loading to my Garmin Edge 1000 - or even the ancient Edge 200 I still use from time to time) d) creating printed maps is simple. It's just all round faster to use than online stuff. I have no interest in performance stats or cloud-storage etc.
It looks like I can get the snap to road to work pretty well with MapMyRide - at least adequate for what I need. AND along the way I've discovered that you can save Mr Google's directions to a .gpx (limited usefulness, but good for the odd occasion)
Anyway, thanks for the contributions.