My main GPS is the Airbox Clarity, and I love it.
On my iPhone for nav I've got the 'Runway' app (also by Airbox by co-incidence) which is a very simple and basic GPS - no maps, but does have a 'nearest airfield button' which lists the 10 or so nearest airfields with their bearings and distance - a nice back up!
Personally, I prefer to have a dedicated GPS unit rather than rely on the Swiss Army knife that is my iPhone....