GPX vs GDB

OK, after all these years of hating Basecamp, I've learned to like it in preference to Mapsource (after many, many updates). My primary objection to Basecamp has been the single database for everything. Now that I've learned to export something that I wished to archive, then to delete it from the "Default" database, it works for me.

Now my question relative to exporting is about whether to choose gpx or gdb format. The gdb file is about half the size of the equivalent gpx file. Does the gdb file loose any data?