We just did it in march on a Fantasy Western cruise. It was Sunday, the first sea day. I think 90 minutes is a safe estimate, but I wasn't tracking exactly how long.
My daughter is 4, and the girls at our table (4 girls, one mom per kid) were up to 9 years old. All seemed to have fun, but one of the older (7ish) girls was way less into it. But her same-age friend was having a WONDERFUL time. The 9 year old was there celebrating her birthday (so, she got sung to) and it was her 3rd time doing the tea. She seemed quite pleased to be there again, but also did not care about most of the presents.
It was not crowded. We lucked out, and my daughter was sitting on the edge closest to the area where they performed, but everyone got an equal turn.
It was at 3pm.
My child was one of very very very few girls there who had not gone to BBB earlier that day. She didn't notice -- was wearing a princess dress, and I'd done her hair "fancy" -- but an older child might have (also, since it was the first full day, she didn't yet know what BBB even was. She might have been annoyed had it been later in the cruise).
There were no boys there with us.
I am a vegetarian, so I got an entirely separate plate of things to eat, even though the table already had the normal spread (most of which I could have eaten just fine). Since I was going to Palo 4 hours later, I let my daughter eat of my plate and there was more for everyone. I agree that it's not a full meal of food, but it's definitely a larger snack than I would regularly eat. And my daughter was able to eat maybe 1/4 of the enormous cupcake. Oh, but my child doesn't care for juice (weird, I know) and even though I had tried to work this out in advance, and tried to tell them when we arrived, they still gave her juice. It then took 10 minutes to get the water she wanted, and she was crying part of the time because she REALLY wanted to participate in the "tea" and really can't stand juice. I am sure this is not a normal problem
The presents are best for 5-7 year olds, I'd think. The jewelry chains are too big for a 4 year old (of course I can adjust, but we had to move all the charms around to make it even close) and the doll is a large, somewhat stiff (and VERY glittery) doll. My kid liked the music box best by far, though I think she'll grow into the rest.
Oh, and we had Tiana, Belle, and Cinderellas as the princesses, but most of the "show" is from Lady Chamomile and Chef Brulee, both of whom were awesome.
We saw Cinderella several more times on the cruise, and she and my daughter had a few long conversations, which was pretty hilarious.