With the map issues, and having now seen how small the Garmin 6xx screens are compared to my Samsung Galaxy Note4 phone, I'll investigate whether there's a waterproof and ruggedized Android tablet (or "phablet" - yeuk!) with a 4-6" screen and that supports GPS and GLONASS, then I can install MM or MMtracker on it and use the existing maps. I can't be the first to tread this path so I'll start another thread.

Garmin and memory map allow you to create Custom Maps if you have access to an image file of the map and know the calibration points of the corners of the map, but this normally a lot of work and is quite tricky to do. Therefore is best biting the bullet any buying the maps.

Sat Map don't provide this facility.

I was afraid of that - this map format issue is a real pain!

Since asking about the Active10 I've become slightly more tempted by the Garmin Oregon 6xx range, but it seems that this will have the same map incompatibility problem.

A thought: I can print MemoryMaps to PDF and then convert those to almost any graphic format. Do the Satmap or Garmin GPS units come with software that can be used to scan and register paper maps? If so it should be possible to import via that, slightly convoluted, route.

Unfortunately no. They use different proprietary images formats.

I'm tempted to start moving over from MemoryMap on the phone to a Satmap Active, but I've got a lot of MM maps on the phone - is there any way to convert them so they can be used on a Satmap device?