I can't speak for the Lowrance or Megellan but I own 2 garmins (Etrex and 60Csx) and I can tell you that they are excellent units. My Etrex was the first European model that came out (8-9 years old) and is still working good (buttons are getting worn out), this is good for a unit that has been bounced around on my work truck and quad, been hunting, fishing, searching and now geocaching. I expect my new 60Csx will prove to be just as reliable.
Hope this helps
Blkhawks