Vienna-Budapest Hydrofoil or train?

The train is comfortable and fairly efficient and will take as little as 3 hours depending on the train you book on. We've done this and it was pleasant enough. Tickets can be had for less than 20 euro if you purchase them in Budapest and I am going to guess they might be a few euro more if purchased in Vienna; a lot more if purchased in the U.S. on line. A relative of mine took the hydrofoil a couple of years ago and wasn't impressed. Bumpy, loud and slow. The website says 5.5 hours and the fares are four times that of the train. My relative also commented that the view wasn't particularly interesting either. Still, it's on my to do list, just not near the top. The Hungarian and Austrian rail companies and the Hydrofoil company web links are on this page (bottom right) http://budapestflat.shutterfly.com/fivedaysinbudapest

I have to agree with James. I found the train very comfortable and inexpensive. It only took a little over 2 hours by RJ.

I'm interested in this question too. If we wait to purchase our train tickets in Vienna (instead of ahead of time in the US), would there be any problem getting on a train? We are looking at going on July 18th or 19th.

I spend a bit of time each year in Central Europe and I generally get tickets in country a few days prior to departure. So far I haven't had any problems but I don't do it a lot so I don't know if I have just been lucky. I would imagine the worse case scenario might be having to take the next train. Between Vienna and Budapest they run pretty often so that might not be a big deal.

I did both. IMHO the train is more efficient: faster and cheaper. Hydrofoil is more fun.

To answer Marianne question: European train culture is completely different than US one. Most people come to the station, buy ticket and board the train. You certainly can come to the station and buy ticket ahead so you don't have to be in line and stressed if your intended train leaves without you. The difference is that in the USA you have one or two trains a day going your direction, in Europe sometimes several in one hour. For example between Vienna and Prague are if I remember correctly 9 direct trains a day and many more with one change.

An addendum to Ilja's post. Yes, historically, people just bought tickets shortly before travel. But more and more routes in Europe are switching to an "airline pricing" model, where tickets bought in advance online are greatly discounted, and tickets bought closer to travel are much more expensive (and may be sold out on popular routes). The Internet has changed the ground rules on many routes (it makes advance booking much easier, so the trains get booked more in advance than they did before, so the train companies can charge more for trains not booked in advance, which drives more people to book in advance online...) Each train situation is different these days, which is why it's important to ask here or do other research before assuming tickets will be cheap and/or available on a certain route. Someone here assumed that Eurostar tickets between London and Paris could be bought inexpensively right before travel, and got a nasty and pricey surprise. If James says he's never had a problem with same day purchase on this route, that's good enough for me. Just don't assume that this will work for all trains.

Never done it same day. Its generally when I arrive in town that I stop and buy the tickets for the next leg. But this comes with no guarantee. I don't worry too much because as stated above there is generally another train in an hour or so but I have never had to go that route. As for costs I don't even know what the online rates are but it seems to me I paid €20 or €30 my last Budapest to Vienna trip. But I really don't do this often enough to be any sort of authority on the subject. I am very comfortable in the region and just don't get too stressed about the issue.