Vantaggi
Lower-ranking people are smart, and dedicated individuals. Gartner's recruiters are great about finding good people. Work-life balance is generally good, but you have to force it, and will depend on the manager. Management > Culture at every step. Benefits are amazing. Healthcare is top-tier and extremely affordable. Vacation time is great, and usually easy to use. Remote work opportunities are nice, but depend on how outdated your manager is.
Svantaggi
Gartner has terrible org. structure in IT. Pretty ironic for a 'leader' of the IT industry, no? Processes are lacking across the board. Internal support is atrocious. You'd think we'd follow our own research and best practices, but that's hardly the case it seems. You'll struggle at every step because nothing is documented. Pay for the expectations placed on you are outrageous. Expect to bounce back and forth between silly escalations (because nobody knows how to say no or put people in their place), projects, user support, all at the same time while trying to do your normal job every day. Then add on mediocre reviews for putting out average quality results. Gartner refuses to make investments into IT resources, more people are needed desperately. I guess that's how they maintain their double digit growth.