I've not stayed at either, but I've visited both.
The HK
Disneyland Hotel is the hotel nearest the park. It is a few minutes' walk away. Alternatively I think they run a shuttle bus, but I don't think that helps too much as the bus station is still a few minutes walk away from the entrance.
The Hollywood Hotel is further away. If you're walking then you have to pass the Disneyland Hotel on the way to the park, and the walk is a couple of minutes longer. Personally I would have no problem walking. Both hotels are convenient, but the Disneyland Hotel is closest.
The Disneyland Hotel is right on the water, whereas the Hollywood Hotel is set back from the water (separated by the pool and gardens). If you're going for a sea view, the Disneyland Hotel probably has the better views.
Personally, I thought both hotels looked great, and would happily stay in either of them. For me, the Disneyland Hotel was definitely more classy (perhaps a little stuffy), whereas the Hollywood Hotel was more fun and relaxed. Based on my visits I decided that when I return I'd probably opt for the Hollywood Hotel.
However, since I've not stayed overnight, I cannot comment on the rooms.