It's been a while since we stayed there, but I just started using this site while searching for a different hotel to stay on our next trip to Disneyland. I suspect that the experience now is the same as when we went, though, and the price premium certainly is :).
We arrived a little before check-in time, but were told they would have a room for us. However, it was uncharacteristically unorganized getting a room. I forget what specific request we had at the time that they (eventually) met, but we kept having to wait around in the lobby in 15 minute chunks, until almost an hour had passed between the time we checked in and the time we got the room, changed, and headed out to the park. It wouldn't have been that big a deal for us to just not go to the room (we didn't even expect it to be ready) until after a few hours at the park, but since they said they'd have it ready, we waited around. If you've ever been waiting around with a 7 and 5 year old only a few-minute walk to Disneyland on their first day of the trip, you know that you don't want to spend any more time than necessary doing that!
Thankfully, that was the only real blip. However, I didn't feel that the hotel was anything special (other than the location). Recently, we stayed at Paradise Pier, and felt that the "Disney experience" was higher there than the GC. The rooms were nice and clean, but we didn't spend a lot of time in them, and I think that is probably the key reason I'm not looking to go back there. The proximity to the park was cool, of course, but not worth the premium, IMO.
On our next trip, DC was the only Disney property available, so we decided to go with a Good Neighbor (Candy Cane Inn, to be exact). I guess that will show me whether the Disney property location makes such a huge difference.
One of the problems in terms of a Disney property vs. offsite property, I think, has to do with Downtown Disney. When they created that, it meant that whatever property you stay in will have a little hike to get into Disneyland. Even the dedicated entrance from GC into CA Adventure is a walk, depending on where in the hotel you are. Once you have a 5+ minute walk, having to go a bit further for a much less expensive hotel doesn't seem to be that much of a problem. Again, we'll see.











