Sprawling across islands, inlets, it is a big place. Architecture has a lot in common with Sweden. Moomins are everywhere, they are a prized cultural thing here. There is a level of indifference to the snow and Ice that Gothenburg cannot match.
There are a surprising number of chines tourists in Helsinki, to the point that a few museums offer translations on the wall in English, Swedish, Russian and Chinese.
The city does not have the frantic building work of Oslo, it feels more settled. Its modernisation, shown in buildings like the contemporary Art Museum are established and it gives the city a sense of maturity.
For a more complete outline see: Helsinki