I have a Garmin GPSMAP 172 with a 4.5" screen that sure makes Maine fog a whole lot easier to deal with. Small screen but certainly sufficient. Garmin vs. others, I don't know. In 5 years of ownership, it just went back for service the second time. My sense is the cost of charts is higher w/Garmin. I have Blue Chart for Block Is to Canadian border and one for Canada to Halifax.
I would also not want to be without depth sounder given our 10-14' tides.