I have been to most "good" restaurants in southern NH over the years. Most of them are decent, but not amazing.

A lot of them are pretty much glorified bars, and their best food are burgers.

I don't really care for any of the Common Man restaurants. They feel like Cracker Barrel to me. Same goes for T-Bones (and their other places like Copper Door). They are decent, but not great. It's a good family restaurant.

For a romantic atmosphere, I would recommend: LaBelle Winery's restaurant "Americus" in Derry, NH. One of the best and most chill atmospheres and amazing food I've experienced in NH. Their steak is the best steak I've had in NH. And yes, I have lived almost 10 years in Texas also, so I know what good steak is.

If you want something more laid back, Jalisco Family Restaurant & Cantina, is a great Mexican style restaurant in Kingston. Tacos are legit.

If you want a good event type experience, there is Jimmy's Jazz & Blues Club, in Portsmouth. I'm not a huge fan of Portsmouth but, that venue is really cool.