Pros
The location, the perks, and the salary make it a very competitive place to work. If you are on the engineering teams, then its definitely worth your time to learn everything as they are a very innovative company in everything that is done. The culture is very young as well if you are out of college, you will definitely make some good friends. Sometimes the work will be very heavy, but the perks and everything you more than pays off at the end. Its not a bad place to start a career, especially if you are doing engineering at salesforce.com
Cons
work life balance is nonexistent. The rapid fast iterations of new products and technologies make it very difficult to have some time off quickly. Stuff changes so quickly that you don't even know.