While I haven't stayed at any of them, I have read a lot about the 3 on-site properties, and it seems like each has something special and different to offer... so, what's most important to you in a hotel?
PP offers the largest basic rooms, and the lowest prices.
DLH has the ultimate in Disney theming, and the best pool area. The rooms aren't the largest, but aren't the smallest.
GCH is the top of the line hotel. The theming is understated where obvious-Disney is concerned. Their basic rooms are the smallest of the 3 hotels. But, you can't get closer that a hotel with it's own entrance into DCA!
So, what "makes" a hotel experience for you--the décor, the size of the rooms, the available amenities, proximity to the parks, the pool, other entertainment/activities at the hotel? While I'm all about proximity and price (hence why I stay across the street in a 2-queen room for $69/night), other people may think the "experience" is more important than price, and are willing to spend much more per night for their room, for their experience. I could give you *my* answer on where I recommend staying, but it would mean nothing without knowing what you look for and want in a hotel.