I just booked this for the Oct 24 Dream cruise. All of your reviews convinced me.
A couple of things people might find helpful -
the concierge booked it for me and said there was a tour at 10:45, and another at 1:15 or 1:45 (I can't remember now - oops). No one's reported an afternoon tour before, so I wonder if it's a new addition. I booked the morning one anyway, so that I'd have the afternoon to relax on the ship.
Although the description on the Disney site says the tour is 1.5-2 hours, the official times are from 10:45 to 1:45, which is 3 hours. I'll find out how long it really is in Oct, i guess.
And a question for those who have done this before -
Do you think this would be a fun tour for someone doing it on their own? DH and I are usually attached at the hip on vacations, but he is going diving in Nassau, so I'll be by myself. Something similar happened when we went to Alaska (he booked a helicoper tour, but I'm afraid of flying so instead I went on a tour of a ranch where they raise dogs for the Iditarod), and honestly, it was kind of uncomfortable - for example, one of the activities was a sleigh ride with the dogs pulling the sled, and they had everyone go on in pairs, only I had no one to pair with. I was kind of feeling like a pariah.

I'm pretty independent normally, and have no problem making friends out of strangers (met a good friend on the bus, and met another good friend in line at the bank

), but for some reason that Alaska kennel trip stuck with me as not very fun.
In any event, excited to see Graycliff and make myself some chocolate!!!