There's nothing between the airport and the city center where the train lets you off. And everything else is 10-20 minutes from the station.
It's really going to depend on timing, day of the week, when you're actually going, airline, etc.
(If it's either March 4,5 or 6, don't even bother leaving the airport as it will be a zoo. The Davis Cup is taking place in Vienna.)
One thing unique about the Vienna airport is that if offers a tour behind the scenes of how the airport operates including a bus tour out among the planes.
http://www.viennaairport.com/jart/pr...ve-mode=active
You will have to clear immigration and customs.
I'm guessing you're flying Austrian Airlines. They allow all passengers to purchase lounge access for 35 euros. Should you decide to stay at the airport this might not be a bad idea as it's more comfortable than the regular waiting area. (WLAN, free snacks and drinks, business center, entertainment, etc.)