ViewRanger was much cheaper to buy mapping for than Memory Map, but prices now have evened out.
I started with just MM, with map coverage of just the South West, and used an old Road Angel to show me the route out on a ride.
I then moved from a Road Angel to the VR app on an android phone mounted to my handlebars, because as Neil says, VR tracks 'ahead up' (like a sat nav), as
opposed to MM which tracks 'North up', which my brain often struggled to translate when coming up(down) to a turn!
I can still plan my route on MM on my laptop, but I save the route as a .gpx file, then open the same file in the free VR webpage on my laptop and
sync it with my phone, which has the £7.99 VR south west map on.
Fortunately, thanks to alot of hard work by some group members, we are able to display overlays in Memory Map, ViewRanger, Google Earth etc
It just takes a couple of rides to get your head around it all.