AIUI the change in MM file format was to comply with OS copyright conditions - any other mapping software would have similar restrictions.
I looked into the self scan option a while back but its just too much effort - even for this freetard.
Its so much easier to download the free MM software & pay £20 for a CAA chart. The picture quality is always good at any zoom level; if you upgrade your computer or change your phone you can always migrate the map licence to your new hardware.
The only difference between the free & paid iPhone apps is that only the paid app allows you to use maps you already own on your desktop computer on the iPhone. You can buy additional iPhone only maps for the free app at a reduced price. I don't believe either version allows you to import self scanned maps.
I imagine the upcoming Android app will be similar.