For me, eight days in Vienna itself wasn’t enough. I loved taking the time when visiting museums and palaces, thus I could easily spend hours in one place :D. So, if you’re pretty much the same type of traveler like me, spending more days in Vienna would be totally worth it.
Walking around the old town was something I could do for days... just looking at the architecture of the buildings, the Hofburg Palace, the old churches, listening to the church bells, the sound of the horse carts, watching the people passing by sitting in one of the "institutional" Viennese cafés eating a piece of Apple strudel, OH... so nice.
Vienna is a beautiful city. What else are we supposed to say? That's right, after all. The architecture of the apartments and churches is enough to occupy me for days. In fact, I spent three days walking the city, from North to South and East to West.