I've got both a GPS72 and a Lowrance iFinder H20. My feelings are for the money the basic GPS72 (on sale now below £100) takes some beating its well built and it floats. Stick in some high quality NiMH rechargables and battery life is ok.
Th Lowrance hasnt been tested in anger, the NauticPath charting is very good and the display stunning. What has concerned me is the design of the battery compartment lid. It is sealed in a way no where near as thorough as Garmins.
In summary if all you need is a basic GPS go for the 72 the different versions of the 60 dont give that much more apart from software and better screen resolution. If you need a map consider the Lowrance but check out the opposition a mate of mine has a magellan its a stunner.
New boat is here, very happy!