Count me as in the "I like Bob's" camp. I think they have one of the best fish to fry ratios of anybody (more fish, less fry). I've only been to Roberts once, but I do remember liking it...a bit more "upscale". Is it the best setting around? No...but in my opinion the food is worth it.
My sister and I enjoyed eating at the Flatbread Company in Portsmouth, NH - they sell organic pizzas that are cooked in a wood-fired oven. My wife used to like the Muddy Rivers Smokehouse in Portsmouth, but it appears that they closed down recently so that's no longer an option.
I've eaten sushi at Sakurabana in Porstmouth a few years ago and it was pretty good.
My wife and I ate the Oar House Restaurant (actually, the Oar House Dock) in Portsmouth, NH and thought it was only OK. It was on the pricey side, and the food that we tried was only OK, nothing really special.
The Oar House
55 Ceres St., Portsmouth, NH 03801
138 Congress St, Portsmouth, NH 03801