Looking for a new gps unit. Would like to stay $400 or under. Want to be able to download the gpx files for campsites and portages.

Right now, I'd say to focus your research on Garmin's lineup. Familiarize yourself with their products and make comparisons (there are many product comparison pages that will allow side-by-side views of differing features). Look for ones that allow additional maps and downloads of gpx, etc via either external chip or internal memory. $400 and under is a good price point, although you might be tempted by models that are just a stretch over that when you see the additional features offered.