GLG is an "OK" place for anyone who just graduated college, doesn't have other relevant job opportunities in their field, needs a basic income and job experience. It will prepare you to better communicate over the phone and bs your next job interview.
GLG's major issues:
1) Inexperienced and at often times juvenile middle managers who condescend those in lower ranks and delegate all their work (there are a few good ones in there, just few and far between!)
2) Bureaucratic, unambitious, and uninspiring leadership
3) Compensation that doesn't motivate (i.e. no true commission in Research and an annual bonus with no specific performance numbers tied to it) *note a new bonus process was rolled out early 2017 that effectively set goals to pay out employees even less than the discretionary bonus previously used*
4) Little to no top down communication as new changes are made and rolled out causes constant confusion
5) "Process Standardization" that has you cold calling as a "Research" professional far more than anyone outside of a Sales role ever should (did I mention you aren't compensated well for this?). Also note that this includes managers reading your client facing emails and grading you on a GPA (and you thought that was all over after school...)
6) Long hours and expectations to behave similarly to the professional services world you work for (BCG, McKinsey, etc.) without the same compensation or reputation to get employed on afterwards
7) Clients that view you as a commodity, NOT partner
8) Toxic political culture on certain teams