Pros
I was at Gartner for over 10 years. I left as a VP of Sales after working my way up from the bottom. Gartner has great brand awareness--it is the best of the best in their industry.
Cons
Unfortunately, as the company has grown, internally the company is rife with the traditional, "the left hand doesn't know what the right hand is doing". Research and advisory teams are in no way aligned with sales, HR is aligned with nobody, product is non existent--legal is spent putting out fires all over the place. For a company that has one of their biggest lines of business advising CHRO's, I've never seen a more dysfunctional HR department--I think they're highly under resourced. I'm proud to have worked there, but standards slipped mightily during the pandemic and there is a lot of dead weight. But because the aforementioned HR issues, expect to pick up a lot of your coworkers jobs--because they make it impossible to terminate somebody for performance.