Like other reviewers here I have been using Delorme products (hardware and software) for many years and have been satisfied. Their iPhone app is very lacking though. To use the app you are required to purchase a login package thats vaguely defined on their website that turns out to be a yearly subscription at $29.95. For this you get maps and terrible routing software that is only web based, has no search tool to start your route or find *anything*. Theres no way to start a route besides using a pan and zoom tool. This is pretty much 90s technology. I have numerous non-subscription topo apps each with their strengths and weaknesses and all of them much better than this app.
Ex BH boy about Earthmate