Pros
Salesforce has a fantastic product with a USP that is unsurpassed in the current market place. Working with the product is great and Salesforce's customers are the nicest I have ever had the pleasure to work with. Furthermore, if you are interested in broadening your horizon and learning, Salesforce will support its employees further than most, even if the subject matter is only loosely related to your job.
Cons
Salesforce is so focused on selling that it neglects enhancing its product to its full capability, looking at the annual report one can see that spend on sales hugely exceeds spend on R&D. This causes much frustration for the employees who are really passionate about the product and its customers. Salesforce is also not very family friendly, work/life balance is none existent and women with family/children will find it very hard to combine work and family responsibilities. The extreme competitiveness that is encouraged by management and enforced by Salesforce's culture also hinders team work and organizational learning.