I would love to stay at the Disney on-site hotels, but the additional cost puts me off - money I can more readily enjoy on gifts, restaurants, etc. Disney on-site hotels work out at least double the price of the off-site hotels (e.g. Dream Castle and Holiday Inn), even as a shareholder and annual pass holder, and I would not pay that. As mentioned above, one really only uses the hotel from 9pm til 9am, for sleep, breakfast and a swim.
I have stayed thus far at Explorers, Dream Castle, and will be at Holiday Inn at end-Sept for 5 nights. I would not return to Explorers again, but the rooms and service at Dream Castle get my thumbs up. The pool at the Holiday Inn looks better (i.e. bigger), but the rooms less plush (e.g. queen size beds for the adults, not king size). But, at £76 per night for 4 people, I can't really argue!
Maybe I'll splash out the cash for an on-site Disney hotel one of these days...