Well as Viennese I recommend Vienna of course if you want more culture, top sights and easy-travelling and sightseeing Vienna is far better but if you want more fun and nightlife Prague might be better though Vienna got a great nightlife though -snip-
[ Edit: Sorry, no promos please. ]
Prague is a beautiful city with a truly valuable monuments scattered around the city. Charles Bridge is the city's oldest bridge, which is the city's most popular attractions, and connects the old town with another bank of Vltava - the small side. Prague Castle is the largest ancient castle in the world. In it are the seat of Czech kings past, kings St. Roman Empire, bishops, and today it is the home of the President of the Czech Republic. Old Town Square as the focal point and a place from which to develop the Old Town, while Wenceslas center of the new town, which was carefully planned and its development started in the 14th century.