I recently switched from Malsingmaps (http://www.malsingmaps.com/portal/) to Malfreemaps (http://www.malfreemaps.com/) because I reckon that I can get the most up to date maps from Malfreemaps. Malsingmaps unlocked versions are few and far in between. Also, with the Malfreemaps I find that I can use the Address feature of my StreetPilot. The free Malsingmap did not allow me to do so.
Malsingmap's locked versions are up to date but one has to be a contributor to get these. Of course I would like to contribute to Malsingmaps but I find the instructions on how to make edits of maps very difficult to follow. Perhaps I need a one to one tutor to go through with me the steps of installing Mapsource etc. and using it to make contributions. It seems to be that this kind of "requirement" puts people who have little expertise with the software at a distinct disadvantage.
I downloaded patch.img ( http://www.malsingmaps.com/forums/viewtopic.php?p=64&sid=3a0f358ec8bde7bab9de679d4ebc3aac) and managed to stitch (combine) some free Australian maps to create a gmapsupp.img for a section of Australia - I did this just to see if I could use patch.img. This is as far as my expertise goes. I understand that Mapsource installed one can see maps on the PC and do editing but I haven't got that far yet.
If you are thinking of doing some simple things with maps you have to register at malsingmaps.com and malfreemaps.com to get access to advice and downloads.