Brought 3 tours for Mexico from Viator, 2 of them happened in reality ( one was really good, the other had a very lazy guide), but for the 3rd one nobody came to pick me up and it was impossible to contact the local tourist agency because nobody answered the phone. I sent an e-mail to Viator's support site but from there the only answer was that I must deal with the local agency now myself. So it was just nice to collect the money and later not to be responsible for anything. Conclusion: as 1/3 of purchases might go missing I won't recommend buying online (and in fact you can get on the spot with the same price or even cheaper). Sorry Viator, you are not on my friends' list any more.