This is just my opinion, but this is the order I liked best of all 3, even though I liked them all and would recommend staying at any of them rather than offsite. The only downside I can think of this one, is that you have to park your car all the way over at the Paradise Pier's parking lot, so it was a pain if we forgot or needed something in the car. (But it is nice to have the parking far away from hotel too.)
1 GC- great convenience with young kids! Like the above posters said, it made a world of difference for the afternoon naps and breaks that kids need. So close to BOTH parks! That, to me, was invaluable! I have heard it compared to a cross between the GF and WL, and I would have to agree. It is DL flagship resort, so they really went all out to make it really regal!
2. DLHotel - it is more kid-oriented. Great place, and to me, it seemed like all the fun stuff was going on over there! It is a quick walk through DTD from the GC, so that is always fun. It has a alot of Disney sentiment, and history.
3 Paradise Pier - A little farther, and a little smaller, and a little bit more contemporary. Not as much of the whimsical Disney feel, but still very convenient to the parks,and always the choice for me if the other ones were booked. Of course at the time I stayed there, they only had the DLH and PP. Now, GC is the place for me!!