Like the other reviewers here, we were delighted with all aspects of this trip. We booked at the very last minute and were somewhat confused about where to meet the boat. So while we were still on the phone to the company receptionist, she had obviously sent someone to find us, because suddenly a gentleman came up and greeted us. This was just the start of a day filled with this approach to service.
Yes, there will still be a 'tour boat' approach to visiting the various sites and grottos, but this is really the only thing one can expect. There are dozens of tour operators all competeing for the same space on the ocean, the boat operators have to cooperate with each other, or it would be chaos. Somehow, our driver, Salvatore, always seemed to manage to arrive at a special site when the other traffic was scant. I suspect this was not just luck.
The ice chest was filled with all types of drinks, including champagne (which our group was happy to sample!). We were 9 on board and it all felt very spacious. We did not know the other people before the trip started, but we parted good acquaintances.
Recommendation: do not be afraid to ask your boat operator for any changes or special requests. They really do want to be accommodating.