I guess it depends on how you use your resort, and what you would expect with a longer stay. If your vacation style includes lots of down time relaxing at the resort, I would choose a better resort. If your vacation style tends to be out exploring and mostly using your resort as a place to sleep and shower, then longer vacation. It is just not worth it to me to do a longer vacation if I choose a less comfortable resort and I want to relax more at my resort.