Pros
MongoDB has been an incredible company to work for, and I couldn't be more pleased with my experience. Mongo attracts top tier talent, and getting to learn daily from your peers is incredible. I have been really impressed with the level of communication throughout the company; and I honestly feel very in the loop with how decisions are made and why they are made. They take internal feedback very seriously, and the company has been excellent with how they have handled covid, work from home, etc. Pay is very competitive, and work-life balance is great.
Cons
Being a top tech company means expectations are high, for everyone; no exceptions. If you are looking for a company to just coast and not be challenged, then this is probably not the place for you. High performers are rewarded, and low performers are coached up or coached out quickly. As others have stated, lots of growth means constant change; but I personally see this as a benefit, as the company is extremely willing to explore and try new ideas.