I use an ipad cellular with a ram mount and run gaia, google maps, google earth, motion x, & magellan TRX. I have just recently started using gaia and am hoping for big things from it as it links open source maps within it. It is the only one other than HEMA that I have paid for. I find each one has its strength and weaknesses. I am afraid I switch around from one to the other and dont really learn the ins and outs before I switch. Gaia will change all of that. Like others, I also carry a gazetteer, road atlas, and paper maps.