The path to promotion is self promotion.
Pros
Besides the obvious (pay and benefits) Salesforce is actually a pretty fun place to work. I can only speak for the sales side and working out of the SF office, I don't know much about the other orgs. Overall they do a great job hiring intelligent social people who will have fun while still working hard. The product is the best on the market and the technology for the most part blows competition out of the water. For me the best part about working at Salesforce has been the people / co-workers.
Cons
Salesforce has an interesting way of recognizing and measuring success, which is mostly driven by tooting your own horn. The practice of "building you brand" is more important to your career than doing intelligent and meaningful work. The company is driven by sales and this causes unrealistic expectations on both the sales side as well as product rollout. Many (but not all) of the low to mid level managers are either unqualified or strive too hard to please superiors. The company is more focused on showing and telling about how great it is than actually being great.