Thanks all for your replies.
The Lowrance LMS 337 CDF has been discontinued and replaced by the Lowrance HDS-5... 5-inch color screen and $799 at Defender. The comparable Garmin unit was similarly priced.
Standard US Basemaps spund adequate for both units... navaids I want, marinas I don't care about.
I am not averse to spending $$, but nor am I an electronics junkie with desire for the very fanciest.... sounds like this is the sweet spot I should be looking in. The comments about fog (where I am not very experienced) gives me pause with only a handheld.
I'm a little confused by some of the refernces to "base" maps. Most if not all Garmin maping handhelds, transportable and fixed mount chartplotters have some type of rudimentary base maps preloaded. For the most part the base maps are pretty useles.
I think what you need to look for are the units that come preloaded with US coastal charts. IMHO opinion the preloaded units are a tremedious bargan. My first experience with one of these units was the GPSMap 478c which in addition to every US coastal chart chart also was preloaded with all US streets. Forget what I paid but I think it listed for $999 but I got it from an online vendor for around $750 maybe 7 years ago. The preloaded charts are a version of the "Bluecharts" without the 3d capability of the "Bluechart Vision" charts.
Preloaded charts were not an option when I bought a GPSMap 3006 fixmount unit five years back. Although that particular unit has been discontinued similar newer models can be bought with all US coastal charts (or inland charts, one or the other). Look at what it whould cost to pruchase either in paper charts or electronically every US chart.
Early this year I got a Garmin Oregon 400c handheld from West Marine for $299 with every US coastal chart. I'm still using the GPSMap 478 as a backup to the 3006 but just could noot pass up what I thought was a great deal.
If I was in the market for a midsized chartplotter and was not locked into a fix mount unit I have the Garmin 640 at the top of my list. It sounds very similar to the 478 with preloaded coastal and road maps except for the touch screen. Use it on the boat or in the car. I believe that it does have the option to be hard wired.