I liked Claudia's the least. This may be because it was the only one I didn't read as a child and I only read it when I entered my 20's, and she's one of my least fave sitter's. (And it's the only one that I've only read once).
My favourite was Abby's, because I loved reading about her and Anna when they were little.
I voted for Dawn's. She is my least favorite sitter (next to Abby). She wasn't that, um, great of a character, and her portrait is, uh, not that great to say the least. The only thing I did like was Sunny, and that was Sunny, not Dawn, so, yeah...
I'm surprised that Kristy's has the most votes! Her portrait is my second favorite (Stacey's being first and MA being third and Claudia being fourth).