bigndaft
I have both a Skymap and a Garmin 430 in my aircraft, but I use SD on the iPad as my primary GPS tool. It uses a lot of juice so I'd recommend an auxilliary power source, but, in terms of functionality, I haven't found anything else on the market that comes close. Some folks say that Airbox for iPad is good as well, but I haven't felt the need to compare the two, as SD is just so good
TTB