Pros
Smart people, stable product with heavily invested customer base. Lots of smart people who are thinking about the long-term horizon. People looking for a 9-5 job with good work/life balance will find opportunities to get a good paycheck for doing honest work. Ambitious people will find lots of projects that need owners, especially if they're willing to take charge/initiative and get their hands dirty doing lots of the work themselves.
Cons
Lots of legacy, software, including many outdated, custom, in-house tools that hamper productivity and adoption of third-party/open-source tools. That's changing somewhat as several influential founding engineers with NIH syndrome gradually lose ground to new hires with better ideas. The company is (somewhat belatedly) embracing the cloud, but leadership in that area is uncertain/unproven. The tide is shifting, but slowly.