Pros
Salesforce has been rated several times as one of the best companies to work for. Salesforce has also won the award for most innovative company for two years in a row. The CEO, Marc Benioff, is incredible. "He pioneered the 1/1/1 Integrated Philanthropic model, by which companies contribute 1 percent of profits, 1 percent of equity, and 1 percent of employee hours back to the communities it serves." (cited from Wikipedia) He is one of the most powerful yet kind hearted men I know of. The products are incredible. They work and really transform how people do business. Besides that they are fun, easy to use and pretty much everything else Salesforce claims them to be. It is refreshing to be part of a company who makes such products.
Cons
The work environment, depending on your location. Headquarters, in San Francisco, is the example for the company and I can't believe any one would not want to work there. Unfortunately, other locations do not share the same culture. At times, you can feel like you work for 2 (or more) different companies. Politics can also get in the way of what should be important. While Salesforce has some incredibly talented people, I was always amazed at how things other than talent seemed to be how people got ahead in their careers. Politics are played heavily, although I think it is unnecessary. I would have expected such at a smaller company or one with less aptitude.