Would you like a proper GPS where you can add custom software? That can act as a mp3 player? Take pictures and shoot video? Be fully waterproof? Then the Garmin Monterra might be for you.
Last summer, 2013, Garmin introduced a new GPS for "On The Trail" use. This means its main purpose is Geocaching and other duties outside.
The Monterra is an excellent device to use for Mountain biking, with its big display and long battery life it can act as a great map during your explorations. The Garmin supplied bicycle mount keeps it secure on the bike as well. The Monterra has ANT+ support, so it can listen to your pulse band and a cadence sensor. As of this writing it is not recorded in the track log. The more or less standard Garmin speed and cadence sensor, GSC-10, doesn't seem to be supported either.
The Monterra can be used for car navigation as well. It even has a special Nüvi mode that let's the unit act more like a car GPS. If you are used to navigate using a dedicated car gps with stuff like Traffic information you will miss it.
One of the main advantages of using a Garmin products is the large amount of maps available.
And the ability to change the maps to your purpose.
Here is an example of the Swedish Topo map as it is sold and is used on a iOS device: