Here's why we've mostly switched to offsite stays...
Onsite is expensive and we expect more for our money. EE added something of tangible value, not an intangible "magic" that seemed more like marketing hype than anything else. Years ago, we never thought we would EVER think this. DH hits Disney overload earlier than the rest of our family. But we all agree that the food, souvenirs... nearly everything onsite is overpriced and subject to (as someone else recently posted) "constant shameless promotion" so that you will part with your money.
We prefer to drive to all the parks (except MK) even when we stayed onsite. We hated waiting in the loooong lines at the end of the day for those buses and boats...
standing on concrete for up to 45 minutes to board a standing-only overcrowded, smelly bus along with a lot of overtired, smelly people (yes, we sometimes went during a hot time of year).
We've found it's just as easy to use a regular Visa debit card or Disney Dollars as it was to use a room charge. Front of the park pick-up is available for all guests' purchases and we didn't have to worry about the last day (no room delivery until next day after 2 PM).
As more offsite resorts are built, more are beautifully appointed and landscaped. Our vacations in offsite timeshare villas have afforded us a level of quality, amenities and space that we could not (or would not) afford onsite. The pool areas are gorgeous. The nearer resorts are as quick & easy to return to, for a midday rest or swim, as waiting for a Disney bus or boat.
We are still able to use our park hopper passes to visit onsite resort restaurants but we are just as likely to visit one of the nice offsite restaurants. We never got much use from the refillable mugs. We can use our full size kitchen to stock all our favorite beverages, snacks, desserts, fresh coffee, etc.
At a good offsite resort, security staff are just as likely to stop and offer assistance as they are onsite. We've experienced this offsite, when we were just waiting for friends to run back inside a moment and DH decided to check the coolant in our van. Security offered to help, though it wasn't needed.
One word of advice to anyone contemplating an offsite stay after only staying onsite for years... if you're going to do it, don't pick the cheesiest, cheapest, oldest Days Inn you can find, then act shocked that it doesn't compare to Disney. It doesn't compare to Vistana, Hilton HGVC, Fairfield or Marriott either. See what you were considering spending for onsite, drop your price a little bit and get the best place you can offsite for that money. Chances are... you may be very nicely surprised!

We were!