I don't, but I can see why people do... In our club we have four GPS equipped aircraft, with four different GPS models of two different brands (including one with dual 430s). It's a pain to remember the pecularities of each one when doing anything more complex than a direct-to! All they have in common is that it takes at least 20 mins with a battery cart to feed them a typical VFR route, using non-database waypoints that have to be added as user waypoints, if you actually want to use them in flightplan mode... Bit of a PITA really...
But not to worry, there's always the map, plog and eyeball!
