I think this has been mentioned elsewhere, but I thought it worth
repeating: Google apparently does not have a relationship with the
Vienna transport folks, so Google maps transit routing is pretty bad.
There also appear to be a plethora of choices of ways to get from the
airport to the hotel. Two, count 'em, two, trains, and a bus, without
even getting to taxis or other options. I stashed what I learned via
Google on the WineConf2015 page.
(My plan is to take the OBB S7 train to Wien Mitte, and then the U3 to
Westbahnhof and the hotel).
Cheers,
Jeremy
