Change is not positive per-se. It can be just as easily negative. I had a Facebook account for exactly two weeks and realized this wasn't an improvement over what I already had. I much prefer quality over quantity when it comes to personal relationships and Facebook really does not satisfy that for me. Besides them being absolutely creepy about the way they position themselves and use the mountains of data they gather about people.

On top of that Zuckerberg seems a thoroughly despicable person which doesn't help in trusting the company that he leads.