I'm an Unofficial Guide girl, and I also use allearsnet.com all the time. I like Birmbaum, but it's too much like the official line for me.
You also asked why - We used Unofficial in 2006, and we found that it gave great information. We did disagree with it sometimes, which is also good, but we felt like it steered us in the best direction. We never went to something that they raved about that we ended up not liking.