It all depends on pricing. I suppose
Disney’s Grand Californian is what would be like a Deluxe Resort (300+ Nightly…rough estimate) - Wonderful and the most expensive. An absolutely amazing hotel. Arts and Crafts of Californian, Private Entrance into Disney’s California Adventure Park and entrance into Downtown Disney. It has the Spa, Restaurants, Snack Shops, Gift Shops, and much more…fab Hotel, its also basically a part of DCA…wonderful views into the park. Its a must see even if you dont stay there. I would highly recommend this hotel.
The Disneyland Hotel is more of like Moderate/Deluxe Resort in terms of Pricing (220+ Nightly…rough estimate) - Its a wonderful hotel, a little more business classy in terms of interior architecture. Has pure Disneylandish magic all though out the hotel from the Neverland Pool to the Fantasia Gift Shops, has lush grounds to wander, great restaurants and lots to do for the whole family, close access to the DTD Monorail station and leads right into the end/start of DTD, great hotel.
Disney’s Paradise Pier Hotel - this is more of the Moderate/Value Resort at DLR (180+ Nightly…rough estimate) - its a very laid back, fun, beachy style hotel mixed with lots of Paradise Pier theming and Disney. Its the furthest hotel from the parks of the Disneyland Resort hotels, but its very nice as well. Nice surroundings, fun walk to and from the hotel, great restaurants, shops and lots for the kids and family to do.
I always recommend all of the hotels of the Disneyland Resort, some people cant always afford them but if you can, go for it and stay on property. Staying on property has all the perks like at WDW…early entry hours every day they’re available at Disneyland, Delivery Services, etc etc.
Hoped that helped, Enjoy!