Pros
MathWorks' product is well established and the company has really good financial performance. Great people around. The product development process is rigorous. As a developer, you need to have formal, written definition the requirements and it got to go through internal reviews before you can start writing a single line of code. Good documentations support. It's a great place to learn Software Development. It seems to be *very* stable in MathWorks. People around stays for 10 years or more!
Cons
Standard big company, lots of meetings to attend, even it's not relevant to you. I have worked in the UK office, and a large portion of your time is spent on making phone calls with people in MathWorks US office, trying to explaining what your code means. Or the other way round, when you have problems using others' code. People stays there for long, that means it's hard to have a change there. My manager there has been a developer for 9 years before transferring to his management role. Another QA guy hsa been there for 5 years. These are actually young guys in the office. There are ones who have worked for MathWorks for 20 years.