The UG's touring plans worked fabulously for DW and I on our last trip. We had all the major attractions done before most people had even arrived at the parks! It was amazing how "right on" the touring plans were in terms of avoiding the crowds.
As far as balance, I think the UG is one of the most balanced guidebooks out there year after year. Is it critical? Sure it is, as it should be. I don't agree with everything in the book, but that's the beauty of opinions. Are the touring plans for everyone? No, and anybody who bothers to actually read the book would know that. An obsession with trying to be clever? It's a 794-page book! If it were nothing but straight information it would be unreadable.
I read the Perlmutter book. A good guide, but in my opinion a little too geared towards upscale couples and families. I got tons more useful information from the UG. Not every guidebook is for everyone. The UG has helped millions of readers enjoy Disney. So has the Birnbaum, the Passporter, Perlmutter and others. I would recommend for most people to pick up several of the guides and find the ones that work best for you.