Ok, I read this thread backwards but it was interesting so I kept going (I seem to read a lot of threads that way lol).
I have only perused Birnbaum's in the bookstore, am on my 4th or 5th copy of UG, and just bought passporter this year.
Like one poster said, if UG doesn't make you laugh it is not for you. I like it because they base their restaurant reviews and crowd/line/when to go info on what appears to be better data, not just opinion. I am a data sort of girl.
I like Passporter because of the neat layout, and places to write things down (this is my first time so who knows if I will follow through and actually bring the pockets to the parks). One thing I don't like is that I will have to tear the thing up to actually use it as designed. What a way to build a market!
I never bought Birnbaums because it is a littly too syrupy for me.
I think they are UG and Birnbaums are the most biased (opposite directions of course). Passporter isn't exactly biased, but it is just some pretty random opinions. But as long as you understand that they ARE biased, they are still very useful.
I guess you could think of UG as the sarcastic encyclopedia

, Passporter as your friendly and organized neighbor who visits WDW a lot

, and Birnbaum's as a WDW advertisement

.
Then there's the DIS, I have learned things here I have never seen anywhere else, this is my most valuable guide!
