Pros
Gartner is full of smart people who are passionate about their work. It's a great place to sharpen your skills and gain valuable experience. Brand is respected in the marketplace and product is high-quality. Sincere focus on diversity and inclusion.
Cons
The "EQ" of Gartner, with the exception of some standout individuals, leaves much to be desired. Communication is lacking around sensitive issues like restructuring, departure of a leader, etc. When communications happen at all, they are sterile and expressions of empathy (if there are any) ring hollow. Many individual managers are excellent, but quite a few senior leaders have poor people management skills. Clearly this attribute is not a required competency at the firm - except perhaps in words only - for all leaders. Additionally, despite a lot of stated focus on women in leadership, individual departments still function like a boys' club. Not because there aren't women in leadership roles on those teams, but because the women on those teams have no real power or influence versus their male colleagues, are held to higher standards and progress less rapidly upwards.