Vienna has the most amazingly comprehensive transport network that includes U-Bahns (undergrounds), S-Bahns (schnell-bahn), trams, buses and night buses. In Simmering where I'm staying we have access to all within 100m of our front door. The U-Bahns and S-Bahns are very well documented, the trams and buses not so much. I'm still not sure where most of the trams go, only that I have to catch the 6 to Quellenplatz and then take the 566 bus (The one not labeled Eisenstadt if its from Suidtiroler Platz - that takes the freeway etc) You guessed it, they have multiple buses with the same number.
The transport network has been unfailingly reliable since day one. If you get on the tram at 7.35 you will get on the 8am bus and be dropped in Laxenburg at 8.25am. Awesome. Not so awesome when you get on the tram 6 and the driver forgets its a 6 and drives the 71 route in the wrong direction :( as happened this morning. One bonus of this slight detour (it took less than a stop before the locals volubly complained) was that I finally got to take a picture of the Enkplatz Church.