Speaking of the Oregon 450, I've been compiling custom maps to use from the published forest service maps on this unit. They are KMZ files and work great on the 450. If anyone here wants these files PM me and I can email them to you. So far I've put together most of the Coronado National Forest maps and some of the lower portion of the Tonto Forest maps (Rolls, Bulldog Canyon, Queen Valley & Pinal Peak).
They look like this on the unit.
I can work on putting together a KMZ file for the Prescott national forest when I find it. Having a unit that accepts custom maps is feakin' awesome!