I have the older Magellan Meridian with SD card. I also bought the Mapsend Topo CD off Ebay and it works fine. The topos have roads, but not hiking trails. Still, they are excellent for topographical information. On my 128MB card, I have most of western Colorado (the mountains) in it. I believe the newer models allow larger cards (mine might too, haven't tried). Here are a few sample images.

If it doesn't have Topo capabilities and a memory card slot, it's just a toy.