Will, the usefulness of the marine database build into the Mariner probably depends on where you paddle. I use a similar model Garmin for general boating in the Puget Sound area and find the marine markers to be both very accurate and highly valuable. You also get the city database, which is extensive, and which I use when traveling by car. I always have my gps with me paddling. Seems to me that there is no reason NOT to get a model with the built-in marine databases for paddling purposes. At worst, it is something you may not need, but I think no matter what, it will be of interest and maybe even often of use. Just my 2 cents worth.

: How useful for paddlers are the built in databases on some units, like the
: Garmin Mariner sold by West Marine (I think it's just a Venture with more
: marine oriented data points)? Likewise, is mapping (eg. the
: Vista)worthwhile on such a small screen?
: TIA,
: Will