Apr 4, 2012 - 8:53 PM
Just a wee contrarian note to Olga, but this may be only my personal experience. I visited Zurich last month from the USA, and bought my Swiss Pass at the Zurich airport train station. I got in line at about 8 a.m. and had my pass in hand about 7 minutes later. This may vary based on your primary currency, but for me, the online purchase would have cost me about $50 US more than buying in person, I didn't investigate why.
Regardless, I adored having my 15 day pass, I visited 20 cities/villages in that time from my base in Rapperswil. It was so liberating to decide on the spur of the moment to do things like say "hey, it's sunny in Arosa today, let's go there!". By the way, you should go to Arosa. And Bremgarten. And Solothurn. And Stein am Rhein. And Sankt Gallen. And Chur, which the guidebooks really do not pay proper respect to (pardon my grammar). I went there twice!