I stayed at the Grand Californian on points for a week last April. Designed by the same team who did The Wilderness Lodge (our favorite hotel in WDW), it is a beautiful and warm hotel. It is not quite the equal of the Wilderness Lodge, but then what is!
Compared to the Disneyland and Paradise Pier hotels, which are not really Disney-themed hotels in the way anyone who is used to the hotels in Florida understands, they are pedestrian--like big Holiday Inns with Disney wallpaper.
The Grand Californian is an immersive experience, and staying there and walking between the two parks and Downtown Disney makes going to Disneyland an experience comparable to WDW.
Even if the difference was 10 to 15 points a night, we would NEVER stay anywhere but the Grand Californian.
Frankly, I think all the naysayers are people who've never been to WDW and stayed in one of the Deluxe resorts there. There is an entirely different expectation between people who frequent the parks in Florida, and those who frequent the parks in California.
And, California Adventure is great fun! You want to get to see the two best rides in the park with no problem? Enter DCA through the special Grand Californian entrance and walk a few steps to both Soarin' Over California AND Grizzly River Rapids. You can do both in a few minutes and then get fast passes for both to come back later in the day. THEN, go see the rest of the parks! You can't beat it.