I think most people will agree you can usually save some money by staying off-site. However, since it can be a different type of experience/vacation when staying on-site, you have to decide if the difference in cost is worth the different type of experience.
Staying on-site, offers the following...
- Disney's Magical Express, a free shuttle to and from the airport, if flying.
- Free transportaion around the "World," no need to rent a car, no parking fees, no direction and traffic stress. Also provides easy return to the resort for afternoon breaks, or the option of spliting up with ease, if somone isn't feeling well, or wants to sleep in late, etc.
- Extra Magic Hours - Each day one of the parks opens an hour earlier or remains open 3 hours later, for guest staying at a Disney Resort.
- The option of booking a package, including tickets and dining.
- Being surrounded in Disney magic. A feeling of leaving the real world behind for the length of your stay.
Off-site offers...
- Lower cost accommodations, and/or more space for less money.
- Many dining options.
For a Disney vacation, we prefer to stay on-site. We have stayed in the Orlando area, to see and do other things and visit relatives, but we can't wait to check-in at our Disney resort.
Either way, you'll have a great time... you're going to Disney!
*If interested in other ways to save money and to watch for discount offers, check this site and also the mousesavers site.