Pros
Good pay Amazing "work life balance". Mental health breaks, missing meetings for family events, generous time off. If you are getting work done, nobody will be on your case. Generally nice people and secure job.
Cons
There's no vision in the company. Most tasks are "a pm wanted to push out a feature in 6 months so he or she could get promoted and move on to a new project." You'll be working on code that's over 30 years old. It's like being an electrician in a preserved 17th century mansion, the asks are simple but implementation is a complex chore trying to navigate such ancient codebases. 80% of engineers just do it because their parents said "engineer or doctor" and they picked engineer, they have no particular passion or competency for the work. The engineering skills you gain will be specific to microsoft or the product you are working on and will not open up opportunities at other companies. (Anyone need an x++ dev?)