I’ve booked tours through Viator for years and only had one problem, that was resolved when I called their customer service number. They are owned by TripAdvisor, so it is a quality product. I like that they now offer a book now pay later option. I used it on my last trip to Hawaii and they charged my credit card on the day promised. However, I did get an email from them beforehand saying my card was charged before it was supposed to but there was no evidence on my statement. I called them and they verified the day my card would be charged. I think the email just wasn’t in concert with the charge date. Make sure you check the fine print before you book. All tours don’t include hotel pick up.