Viator Tours Rome

Viator is a consolidator rather than an actual tour company. You would be better off booking with the tour companies directly.

Yes, I have used them 7-8 times. Yes, they are a consolidator, but it is a good site to visit to see all available tours. Whether you book through Viator or directly through the actual tour company is entirely up to you. To find the actual tour company you have to go deeper into the tour booking information. Sometimes the prices are the same and sometimes cheaper on the tour operator site. I have never had any problem with Viator when booking a tour. It is just a conduit for the tour operators to expand their business. Similar to any third party site such as Booking.com for hotels or Kayak for airlines/car rentals or Skyscanner.

As stated above, Viator is a consolidator for the companies which actually operate the tours. As Viator charges a commission for those companies to list on their site, tickets/tours usually cost more than booked directly with the tour operator or the ticketing site for an attraction itself.

Reliable? Probably so but there's at least one exception: the Colosseum, especially Colosseum tours which include the underground. These tickets are so difficult to get that even the tour companies are not always able to lay hands on them: they sell the tours in advance HOPING they can do that. There are any number of posts from tourists who've had their tours cancelled late in the game when that didn't happen, such as this one:

https://community.ricksteves.com/travel-forum/italy/colosseum-forum-palatine-hill-tour-canceled-6-days-out-by-the-roman-guy-tours-any-options

It's also possible to have your original tour time cancelled and rescheduled to a time that might not work for you. It doesn't seem to matter who those tours are booked with: if not through Coopculture - the official ticketing site for the Colosseum, Forum and Palatine - there's a risk of reservations falling apart. Trouble is, the tickets are in such high demand that trying to get them through Coopculture can be a painful or even futile process! 😬

I bought a tour through Viator and the guide was a complete no show. Now this was the problem of the actual tour company, not Viator. Although I had their contact information, it was useless. Viator quickly refunded my money.