$250 is very high for Paradise Pier, which is the least expensive of the three hotels, so I am going to have to guess that a luxury room is going to be on the concierge level and/or has a park view. The park views are great! I believe that one benefit to concierge level is that is has snacks available for most of the day, so if you are going to be in the hotel during the day, you can save some money on meals by taking advantage of the snacks. I have not stayed at the Grand Californian, but from what I hear it is a luxury hotel, and I've heard rave reviews about it. It is supposedly more themed than PP and has more of the park view rooms available. The GC is the closest to the two parks and has a private entrance to California Adventure. The PP is across the street and a small walk away, and has a different private entrance to CA.
HOWEVER, because I never stayed at the GC, take this with a grain of salt. My hotel of choice is PP because they are less expensive. I hear that they are getting a complete refurbishment that should be done in May, and the new rooms are supposed to be beautiful, with more of a beach theme. The regular rooms are more on par with $160 a night, but sometimes you can get a special that makes it less.
GC has a mountain lodge theme, and not so much Disney, but they do seem to have more amenities available, such as some of the rooms have bunk beds with a trundle underneath, so three kids can have their own beds.