Hi, Silver Traveler,
I guess "worth it" depends on your definiton. I think if we'd done this trip on our own, we all would have gotten sick at some point due to there is just no good way to judge the food and sanitation there. With Disney, we felt very safe. I think some people just have more sensitive systems than others.
DD and myself felt great the whole trip and never got sick, except for some very mild altitude adjustment. DH was sick after the feast night, but I would blame that much more on the fact that he ate huge helpings of everything offered, which was quite a lot and quite varied, and also drank the pisco sours like it was his job. He forgets that he is not 25 anymore. He was ill the next day until lunch time when I finally told him to stop grandstanding and take some immodium, aspirin, and gatorade. The combo had him all better in about 30 minutes. (He's one of those who hates medicine and believes he can tough things out.)
Cipro, as I understand it, is a drug that targets bad bacteria in your gut, sort of an antibiotic that works in fewer doses. The guides carried it, but it did not seem to help the woman on our trip who had tummy problems and took it. She told me that she always has tummy issues when traveling, so this was not something specific to this trip.
DD and I got Hep A vaccines and tetanus boosters before we went. DH was Army once upon a time, so he has had every vaccine known to man. You will only be in altitudes where malaria and yellow fever are not a problem, so you do not need those. In fact, we never encountered mosquitos, although the gnats at Macchu Picchu were awful.
We purchased airfare in Dec and it was $3200 for the three of us RT.
I hope this helps. You will LOVE this trip - it was just so amazing!