Outer Limits 4x4 Board

Just got hold of a magellan meridian platinum GPS cheap.. It has the north america basemap in it tho..

I know you can load in maps from mapsend and discoveraus.. what are peoples thoughts on these products.. and what are the best options.. and where can I "buy" those options....

cheers
daniel

I use 64mb SD cards to load the maps on, each card holds one state.
I use discoverAus, You can also connect it to a laptop whilst drivering for a bigger/colour screen and a couple more options become avaliable.