Here's a thread from this past March that basically asked the same question.
I'm surprised it didn't get locked. :mrgreen:
It contains the information and answers that no doubt will show up again here. ;-)
http://www.quiltingboard.com/t-107050-1.htm
And what made the winning quilt not the best of the three?
You'd be surprised how important the binding is in shows. So, all things being equal, the top prize could be decided on that. Or the quilting - did it fit the pattern? Did they all have pantos or custom quilting? Crappy custom quilting could lose out to a well executed panto. Did you inspect the back of the quilt? Maybe it was full of bird nests.
Or maybe you just don't particularly like a style of fabric - they weren't all made from the same fabrics/colors.
I know I tend to look right past Civil War and Aunt Grace quilts. They don't even register for me. But that doesn't mean the AuntGrace quilt wouldn't be the best one if I were judging. Conversely, since the judges are human, it very well MIGHT have entered into the decision making process. I've heard a judge mention in an aside that she has a problem with yellow but she works really hard to keep that out of her critique.
Who knows?