My son is four and my daughter is six!
We have done BBB before and my daughter LOVED it. She truly LOVED it and was able to have a magical moment with the "real" Fairy Godmother (that's exactly how she told everyone about it, doing her hands to show quotes -- ha ha).
Anywho, we have talked about another trip in the future (our Nov trip is a surprise) in a round about way and I think she really wants to do BBB again. I asked her if she'd recommend BBB or PL for a friend I know from work who's already done BBB before and the brother is doing PL. See how I tried to get her opinion without letting on - ha ha.

She knows the little girl, so it's totally buyable.
So, we are doing BBB for DD and PL for DS. We have the BBB appointment at 8:15 a.m. and PL at 10:00 (I think those are the times). So, we will all go and watch DD get beautified and then we'll travel over so that my DS can get pirated! We'll be all done by lunch and I'll be traveling MK with a pirate and a princess.
You know your kids best. Is your little girl a total Princess who loves pink and sparkles and fairy dust? Then, BBB is for you, they really do a great job with the girls!
I've never done PL so I can't really speak to that, but I'm so looking forward to letting my son experience it. He's a huge Pirate fan! We're also going to do the Pirates and Pals fireworks cruise for him because the last two times we've done breakfast with the Princesses. He's a good sport (and total flirt), but this trip he gets a special treat too!
No matter which way you go, it will be memorable. Bring the tissues...I cried like a baby when we did BBB for my peanut! Expect more of the same with both of my big kids this time. Even my baby is getting in on the action...she's getting her first haircut at the Harmony Barber Shop right after we finish up with PL
Have a wonderful trip!!!!