One of our DIS-ers, Bumbershoot (Molly), would be an excellent person to speak on this subject because she has stayed at all 3 DLR hotels in the last year - actually, I think in the last 6 months, maybe?? - so she can give a sort of fresh, current rundown of the pros and cons of each one.
I have stayed at all 3 hotels more than once but my last stay at the PPH was in December 2008, my last stay at the GCH was in December 2007 and my last stay at the DLH was about 15 years ago!!! However, I always end up on the GCH and DLH property even if I stay at the PPH, so I can get a taste of all 3 places in each trip.
The PPH, unfortunately, suffers from lack of space upon which to build or expand, so while they have a very cute sun/surf/nautical theme going on, they can't really develop that theme to the fullest extent. PPH is basically one lone building and a parking structure. You see traces of this beachy/ocean theme in many places - the sun is prominent in several areas, there are Mickey Lifeguard lamps in the rooms, surfboard room number signs, seashell soap dishes in the bathroom, and sort of pastel blues, greens and pinks in the rooms and hallway carpets. There is a pull-out bed/daybed in all of the rooms, and they are fairly spacious. Also, in the bathrooms are the festive 'Mickey Ears' bath products, sitting atop a surfboard. The lobby seems shiny and upbeat - a little more 'fresh,' in my opinion than the DLH, and features a Surfer Goofy statue to greet guests as they walk in. Yes, the wait for elevators can be a bit bothersome and long, but it has never been enough to keep me from staying there. The best part of the PPH is the fact that it is the least expensive of the 3 hotels, so it is a cheaper way to get a taste of Disney magic and the perks of being a hotel guest. The PPH is located across the street from the GCH and DTD and the main hub of activity.
GCH, as previously mentioned, has a gorgeous, huge lobby area with a fireplace and a piano player and comfy, warm, welcoming chairs and sofas for weary travelers to plunk down in (even if you are not staying at the GCH). To me, the GCH is very reminiscent of a sort of elegantly rustic mountain chalet in decor and vibe, with rich dark wood and dim lighting and very high ceilings. You will not see much in the way of Mickey in the GCH (however, there is a cool hidden Mickey in the grandfather clock in the lobby). The rooms seem very dark to me, in contrast to the much brighter rooms of the PPH, and they seemed small to me. There are no Mickey Ears bath products in the bathrooms - instead, you will find H20 Spa products. There is a nice pool area, which is prettier than the pool at PPH but doesn't have the nifty water slide that PPH has. As for convenience, yes, depending on which room you get, the location can be excellent and save tons of time going to and from the parks. When I was last there in 2007, we had a great location and so being that close to the parks was irresistible! However, not all rooms have that great location. If you get into a room with a DTD/fireworks view, you will most likely be traveling down endless corridors to get to that room, therefore negating the convenient proximity of the GCH to the parks.
Again, I have not stayed at the DLH in 15 or so years, so I cannot really speak to the condition or style of the rooms these days, but the DLH grounds are sprawling and lush in many places, and there are lots of character touches around the property. There are hidden Mickeys and other hidden characters in the hallway carpets. There are character topiary bushes. There is a lovely koi pond and gorgeous waterfalls. There are fun mini-remote controlled Jungle Cruise boats to play with. There are bronze character statuettes in the main lobby, and a giant Mickey statue outside of the main entrance to the hotel. There is a fun themed pool area. Plus, there are 3 towers, so the numbers of rooms far exceeds the rooms in the PPH. Also, you will find the Mickey Ears bath products in the DLH rooms.