Late October is still hot in Florida; therefore, it's pool weather.
I love both parties. Both parades are top-notch, with very catchy songs. I've never done this, but sometimes the Halloween party is on Nov 1, and Christmas Party is on Nov 8, so you maybe to fit both parties into one vacation. Comparing the amenities of the parties, the character greets, fireworks, and parades are a wash, but I like the complementary cookies of the Christmas party over the Halloween Candy. I also prefer the Christmas castle stage show over the Halloween one.
Outside of Disney, Christmas is my favorite season, as I love the classic Christmas music, movies, and decorations. That said, if I had to choose between Halloween and Christmas parties, I would select Halloween because, as an adult, there are very few things to enjoy about Halloween outside of Disney. Outside of Disney, I only like the fall decorations of the Halloween season, but I am not into the horror or ghoulish side of Halloween. The extent of horror things I like are Haunted Mansion, Tower of Terror, or an Alfred Hitchcock movie. The Halloween Party hits a home run with the "Not-So-Scary" theming. It's the highlight of the Fall season. Dressing up in costumes as an adult and interacting with the characters is fun.