I use Scenic Maps on my wifi iPad along with the Dual XGPS-150 bluetooth gps puck.
I like that the maps are already there and I don't have to download them the way you do with Motion X. It would be nice to have higher res maps but the lower res maps are workable in most situations.
One feature missing is you can't import a route. Instead, I input the main waypoints (Y in the trail, etc.). Good for navigating when the trails are there on the map. There have been times when the trail wasn't there but it was easy enough to find a trail/route to the next waypoint. I can see where this could be problematic in the future though.
Hopefully the developer for the app adds the ability to import routes soon. IIRC it was one of the things on their list of features to add.