Buda & Pest are wonderful, no doubt, with easy access to both Vienna and Bratislava (via Danube). I would avoid it now because Hungary violates basic human rights - a situation which is deteriorating as a result of the rise of the fascist Jobbik party:

http://budapestbeacon.com/news-in-br...cizes-hungary/

My vote would be for Prague - the Charles River, architecture undisturbed by WW II and the best public transit.