I stayed at the Park Place Inn in November 2005. It was very close and I liked that about it. I just got back from a trip earlier this month and stayed at the Ramada Inn Maingate. It is a bit farther to walk to (3 or 4 hotels down from PPI), but I preferred it. I thought the rooms were nicer and the hotel atmosphere was better. My room also had a good view of the Tower of Terror! I would definately stay there again.
I've stayed at many of the other good neighbor hotels too, but mostly when I was younger, so I can't give a real good opinion. I think every hotel is cool when you are a kid.