annie2871, it is somewhat hard to answer your question precisely. But, here are some general thoughts.
The main difference is in the price of the lodging. Generally speaking, the cost of lodging is higher during Christmas week until the first week in January.
If you shop early and intelligently, you can get very good selection on lodging during Christmas week.
Both summer and Christmas seasons have their pluses. If you want to come to swim, of course, summer is better. If you want to see the very great Christmas decorations, then that is the season for you.
Hope this starts to help you begin your decision making.