The old parts of the city are still the same, preserved historically. Parts of Portsmouth predate the USA by a hundred years. Most of the new development is on the periphery of the city, though there are is some new commercial development near downtown but outside the historic zone.
Concord has seen far more improvement. When I got here in 1993 it's nickname was "City in a Coma" which was sadly accurate. Now a days, it feels more like Burlington VT.