Pros
The biggest pro for MuleSoft are definitely the employee's themselves. You will realise from the very beginning that you are working in an environment where everyone treats themselves very nicely, where everyone is passion about the products and the vision of the company. They are all very smart, talented group of people where you feel you can grow to new heights personally and professional. The on-boarding feels very organised to get you up to speed as fast as possible. You will have "todo" lists, shadowing, kickstart training, product training, etc.
Cons
So far I haven't seen any big cons which I would take seriously. You have to aspect that MuleSoft is a fast growing company with a great future. There are tons of opportunities and a lot of work to do, but this is more a pro rather than a con if you like challenges.