Pros
People have to be relatively smart, personable, and capable to get into Gartner. Still, I noticed a steady decline in quality of associates and more of a "hire and fire" type environment toward my later days with the company. It does depend on the business unit, though. Gartner offers internal mobility assuming you are based in one of its major offices. Benefits are pretty solid, though a more robust ESPP would have been appreciated.
Cons
Your experience at Gartner, like with many companies, depends wholly on who your manager is. Some managers sit around doing nothing, some micromanage so they look good in this very political environment. A vast majority of managers only "manage up" and don't really care about their subordinates' career development. For recruiting specifically, Gartner feels almost exactly like agency recruiting, complete with internal competition as recruiters and sourcers are vying for the same candidate profile to fill an array of different positions (especially among the sales teams). You are a number and you've got all the KPIs and pressure to perform of an agency. The biggest difference here is that you don't get the commission checks of agency recruiting. You'll be 90% base salary, 10% performance bonus and whether you make 1 hire or 100, you get paid the same as your stack-ranked cohorts. Why enforce agency style recruiting practices if you don't align that to agency-style bonuses? Antiquated IT systems that result in reduced productivity. Repetitive manual tracking is required by each recruiter over several systems including Avature, Google Docs, Workday, and quite often more depending on management style. Workday is the primary ATS for recruiting and it is very inconvenient to use.