Can someone explain the difference with these units? I'm looking for a new ff for my kayak, and there are 3 price points for each of the GPS/Preloaded/Navionics options on Lowrance's site without much definition. 

This can be confusing and not only is there a difference in the GPS and mapping, but also a difference in the transducer bundle (TripleShotTM, SplitShotTM and Bullet).  The least expensive version is the HOOK2 fishfinder-only models (with the exception of the sonar-only HOOK2 4x Bullet) which includes a built-in GPS Plotter (without charts) for saving waypoints, following trails and navigating to favorite fishing spots.

The second option comes preloaded with C-MAPS.  The third is preloaded with Navionics +.  When you buy the bundles I think you will find a cost savings over buying the unit and map card separate.  The most important part if you are unsure is to have the onboard microSD slot providing expansion possibilities for optional chart cards.  I personally like the user friendly Navionics charts and the ability to use the Navionics apps for IOS and Android phone and tablets to help plan my fishing trips.  I use every resource available to ultimately catch more fish.  Best of luck on your search!

 

Semper Fi and Tight Lines, <><