There is something to be said about community. In defense, I would probably say that Mr. Excel has more "experts" on their forums who are able to provide answers, so there is some benefit to being to quickly get answers from multiple sources. On the technical side, I think their forums works a little better at uploading workbooks and posting code.
However, Chandoo is where I'm the most comfortable. As you said, it starts to feel like we are all friends here, and we develop a sense of "camaraderie" with our fellow regulars, such as yourself, Hui, SirJB7, Narayan, fred, bobhc, and many others. =)