We did the BBB at MK last Labor Day for my daughters 6th birthday. She is very girly and loves the princesses. I had bought her a nice Sleeping Beauty dress and shoes from the
Disney Store earlier in the year on sale and let her wear it the day we went to MK. We had an early appointment- 8:00 or 8:15 I believe, and as we were walking down Main Street, we surprised her and told her she was going to get a princess makeover and then eating breakfast at CRT. She was so excited, running and screaming "this is the best day ever!" Exactly the kind of reaction you want!
We checked in, and while there was a small line and things were slightly chaotic at the entrance because it is small, but we were seated right away. The whole process took maybe an hour?
She LOVED it! She loves feeling special and pampered. It was so cute inside with all the little girls getting all done up!
She did get a lot of attention afterwards when we walked around the park, but not really much more than any other girl in a princess costume I would imagine.
Since we had the dress already, we went with one of the cheapest packages that is hair, makeup, and nails, and it maybe came to $50? Totally worth it in my opinion! I don't think I would ever pay the price for the higher packages.
We also just did Pirates League (see avatar pic) last week, and she chose the mermaid package. That was cute too! I asked her which one she would like to do again this year for her birthday and she chose BBB again.
Good luck in your choice! Maybe you could give the girls some options and let them choose?