I would not recommend Harbor Sounds to someone who just wanted a quiet, romantic meal with their spouse. Might be OK for a big group, though.
I agree with RoseRed. One other that I would add to the list is Old Field Inn in Prince Frederick.
Out of all the restaurants mentioned, Brome-Howard is the one I'd place at the top of the list with Old Field and Dry Dock tying for second. Spinnakers is good, too.
I've had some bad experiences at Cafe de Artistes. Found the food mediocre and every time I've been there, they've rushed me through my meal. If I'd wanted fast food, I'd go to McDonald's.