Budapest last year was excellent. It was a national holiday as well so accomodation may be a problem, we took a tent and found a decent campsite within a taxi ride of the centre. For the race we just turned up and found a spot on the Danube between Parliament and the Chain Bridge (The Bridge was closed as the start/finish goes under it!). No tickets and even though the crowd was huge (over a million I am told) no problem getting a decent view. Commentary/presentation (big screens) was good and in English as well as Hungarian.