I have been using a Garmin 60 CSX for several years. Last year on the TAT, I found it really limited on memory. Storage was 20 tracks, 500 (I think) points.
When I got back I tried out a Garmin GPS Map78. Storage on this is 200 tracks at 10,000 tackpoints each track. I could load the whole TAT on it, ot the entire Blue Ridge Trail, which I did and made several excursions on. Unit is a Marine unit (supposedly) uses the better 4 prong plus and rain hasn't affected it yet. I really like this unit and have now bought three off ebay, arounf $150.00 each and sold my wife's 60CX. These have been discontinued now by Garmin in favor of the Montana/Montera series (much more expensive) but can be found new in box still on Ebay.