Lots of misinformation on this thread.
It is not correct that there are 5 princesses at both Cindy's and PSB. There are 5 CHARACTERS, but not necessarily princesses.
It is also not correct to say that PSB (Akershus) is a buffet. There is a cold buffet, but the hot food is brought to your table, just like Cindy's.
We have done both Cindy's and PSB. The atmosphere at Cindy's is way better. There is something about being inside Cinderella castle. It is like nothing else. The food at either place is just so-so. You're not really there for the food. It's fine, but it's not fine dining....
Whether you will get more princesses at one or the other is impossible to know before-hand, as they don't tell you which characters will be there.
In my experience, we only had two princesses at Cindy's - Cinderella and Belle. The other characters were not thrilling for my daughter: Mary Poppins, Fairy Godmother and Alice in Wonderland. They were fine, but they're not princesses. At PSB, we had 4 princesses and Pocahontas. We saw Ariel, Belle, Jasmine, Aurora (Sleeping Beauty), and then Pocahontas (who was a show-stopper).
Different people had different experiences. If your little ones are big into Cinderella - then you should try for the castle. If they're big into Ariel (like mine), then there's a good shot you'll see her at PSB. If there's one particular princess you want to see, you can maximize your chances of seeing her by checking these boards to see which princesses routinely show up at which meals. I noted that Ariel tended to show up at PSB lunch, rather than breakfast, and so, booked that meal to maximize our chances of seeing her -- and YAY -- she was there.
Good luck!