It took me about 2 years to get the hang of the sandpaper/mousepad system but now that I can do it I love it! I can touch up the edge on my Battle Rat in just a few minutes with 400 grit paper and maintain the convex edge, which I happen to like. I consider sandpaper to be fairly cheap although it does wear out fairly quickly.

For my knives without a convex edge I mostly use the Spyderco Sharpmaker along with a set of Spyderco bench stones.