Be careful when you buy ticket. Even if you buy ticket online, you still have wait in line to register at the desk on the bus station . Then you get your paper ticket . You need this to get on board. The e-ticket is not accepted There are buses that leaves at 12 and 1205 o clock if you miss your bus you cannot get on the 1205.
Webpage is user friendly. The only issue is tickets are OVERPRICED ONLINE! The ticket is 143 Bahts which is roughly $4. But you will pay more or less $9 when you buy online since they will charge additional fees, commissions etc. So better go buy it at the bus station if you have time. In the worst case, the bus will be full and you will wait the next one in 30-60 mins.
Also, nobody cares about vouchers. Even if you buy the ticket online, you still have to get in line in the bus station to have a printed ticket. So FYI.
Firstly, not very managed office counter. Secondly, it seems unnecessary to stand in line even after having a confirmed ticket from 12GO. That defeats the purpose because you're still standing in the same (LONG) line for a 143 THB ticket which you have already paid 197 for, online, and can't even get on the bus directly by showing the QR.