Like Gesundbrunnen and Ostkreuz (with restaurations soon to be completed), Südkreuz is one of the modernized train stations of Berlin. It looks like any modern train station.
ost of Berlins dirty and rusty buildings are what gives the city its scarred but very lovely face. Ending up in Südkreuz or even Hauptbahnhof turns your impression of the city upside down.
That said: I love the shiny metal facades.