How reliable are these buses in Shanghai?

I'm planning on travelling from Hangzhou to SHPudong Airport in February, to catch a flight to New Zealand. I'm a bit dodgy on the whole 'Chinese traffic' thing, it hasn't been kind to me so far.
First question, is this as reliable as taking the train? (And a taxi after that)? Second question, can the ticket be bought on the bus in Hangzhou, or do you have to visit the CAAC ticket office / Huanglong Sports Center?

Cheers in advance