Much of the old town is narrow streets and decaying buildings but full of character. It's being slowly 'done up' (a UNESCO heritage site since 1982) but the emphasis is on slowly, which in many ways is a good thing. No quick-fix Disneyfication here.
Just to the west is the grander, more open town centre dominated by the Capitolio Nacional. Built in the 1920s, it was modelled on the Capitol in Washington DC (and is apparently an inch higher) and used to be the home of the Cuban government. But it was deemed too 'American' for the Castro regime so the government moved out & has struggled to find appropriate tenants ever since.
Flitted between the two really. Spent a couple of hours in the voluminous National Museum of Cuban Art, had a coffee in Ambos Mundos, the hotel where Hemingway wrote several stories while running up a huge bar tab, viewed the city from a wonderful rooftop camera obscura in Plaza Vieja, and ended the evening in little retro-trash cafe just a block behind the Capitolio, but it might as well have been another world.