I studied it as I was preparing to live in Shanghai for a few months. I found it very interesting. As an English speaker, I thought Chinese grammar was fairly easy (as opposed to Korean grammar which is not easy in ANYBODY's opinion :) ). I thought pronunciation was challenging, but I found a very good way to study that.
Reading turned out to not be as difficult as I thought ... although I did often get confused on where to break some compound words which gave me a few good laughs as I realized my mistakes.
Very interesting language, though.