Pros
Good reputation in the field. Very generous PTO.
Cons
I joined Gartner via acquisition as it acquired my old company (let's call it) ABC. We at the time were excited by this even though Gartner's many stakeholders questioned the deal. Then turned out Gartner only wanted like 10% of ABC. So it has been breaking up ABC and selling each part, yet at the same time, integrating things. So while worrying about being gone tomorrow, you still need to spend time integrating your email to Gartner. So that's fun. Gartner appears to have most of its software engineering resources in its India offices. During a time the country is trying to "Buy American, Hire American", Gartner laid off its US employees and gave their jobs to India team without blinking an eye.