Viator

First of all, Viator is a booking service and the company does not conduct tours. They book people on tours by other companies, and if you want such a tour, you are usually better off choosing one of the tour companies themselves, some of which are excellent. Second, you don't say where you are going to Pompeii from. If that is either Naples or Sorrento, it is an easy and very inexpensive train ride of 30 to 45 minutes or so, right to the entry of the ruins. If you are staying somewhere more distant, then maybe private transport would save you time, although probably at a considerable cost. Finally, I recently toured Pompeii without a guide, and wished I had one. There are a number of good guides available right near the entry, speaking various languages, at modest cost for generally 2-hour walking tours. They know the ruins and history thoroughly, do not get lost looking for things which you very well might, and they know which streets or sites may be closed or cordoned off for renovation that day, which no written guide or map is likely to include. I found, for instance, that the street names in the RS guide and map did not correspond to the street signs at the ruins, which made it very hard to locate specific sites. You can select a guide whose personality appeals to you and whose English is easily understandable. The ruins at Pompeii are very spread out. You can always stay longer and poke around on your own, even after a 2-hour tour. For lunch, there is a basic but decent refreshments place within the ruins, or you can easily take and carry a panino or snacks (and water!).

If you'd like to tour the scavi on your own, Pompeii is usually very easy to reach by train, especially from Rome, Naples, Sorrento or that general vicinity. Why pay for a tour at all if you're not going to use it?

Let us know where you're traveling from, and RS members can help you do this independently. We've done it from Sorrento, and could have done it just as easily from Naples or Rome - although from Rome it's a pretty long day.

I have used Viator in Milan (1/2 day city tour - including Last Supper)
Venice (evening walking tour - including a gondola ride)
Rome (Vatican tour 1/2 day - included museum, Sistine Chapel, and ending in St. Peter's with plenty of free time.)
They are consolidators and I really enjoyed every one of the tours I took. The guides were all native English speakers, art professionals, history teachers, etc.
I would highly recommend them.....I found the prices to be very reasonable.