I visited Vienna and Prague in October 2007. Prague was by far a more interesting and friendly city. Vienna has a cold, Germanic ambience. The staff at the Marriott were rude and unhelpful - almost like we were intruders rather than guests. In contrast, everyone in Prague were friendly. Prague is also far more picturesque than Vienna. I know, this is all a matter of personal taste. I have no desire to go back to Vienna but I look forward to my next trip to Prague.