I have not used TPE yet on a foray.
I use DeLorme Topo 9.0 [http://shop.delorme.com/OA_HTML/DELi...inisite=10020] on a netbook for offroading. The netbook is mounted in a stand that holds it above the transmission lever and I can swing it out of the way. Topo can show either a composite topological map and spacecraft photographs, or the two side by side. I netbook runs at 1.6 GHz and even with all the memory installed, the netbook is too heavily worked to consider also running TPE. I plan on using TPE before I leave home since I do not want to drive around with two netbooks/laptops.