I agree with Providence. It gets crapped on and is a nice city. Terrific restaurants, good arts & music, even has some good breweries, especially Long Live Beer Works.
Burlington, Savannah, Charleston are terrific, but not underrated.
Kansas City is underrated. The Plaza area is really nice, and they have done a terrific job creating interesting spots for dining, bars, music etc. Long a center for Jazz and Blues music, and of course BBQ. Few cities have upgraded themselves the way it has over the last 20 years. Curious if
@ZooCougar agrees.
Aiken, SC is quite nice. It's across the river from Augusta, GA. It is loaded with horse farms, and is an equestrian center. It has a really nice downtown area, lots of outdoor dining and it has become fairly young and vibrant, in part due to the growth of U SC - Aiken.
Worcester, MA is closing in on being underrated. It doesn't have a great rep, and still have some work to do. But the downtown is pretty decent, it has 3 colleges, several breweries sprung up, and now the Red Sox AAA team has moved in to Polar Park, which is going to include a new dining/bar area. It is a biotech hub, and given that it is still inexpensive, I think it will be a target of increased gentrification. Loads of gorgeous old homes.