We did the tour in June and had a great time! My daughter loves elephants, and I find them fascinating, so I booked as soon as I could. I don't know how many people can be grouped at one time, but when we went there were only two other people aside from us, so five in total as my aunt came along too. I read another review on here where it was just the two of them. You're transported to the area in a minibus type vehicle and I believe there were seats for 16.
As for the tour, it's what you make of it. An animal ambassador meets you when you get off of the bus and is a fountain of information regarding elephants. Our ambassador was Ashley, and she both offered information on her own and answered questions that were asked. There's also a cultural representative full of information, and it was really eye-opening to learn about how elephants are viewed in Africa, the steps taken to prevent poaching, etc.
I say, go for it. It's cheap and not long at all, but the chance to get that close to these beautiful animals is fantastic! It was wonderful just watching them go about their daily activities.