Pros
The partners (and VERY select junior staff) are the groups greatest assets, as they provide a wealth of industry-specific knowledge you'd be hard pressed to find at other firms. If you're in a position where you're managing projects, you can set your schedule such that you don't need to travel to the office every day of the week.
Cons
Sigh..I could write a small novel but let's keep it high-level(ish) Contrary to what they tell you in interviews/selling, IMSCG does NOT have access to IMS data, with exception to very select slivers. Why is this? Well, because IMS is a BIG DATA company, not a consulting firm. Earnings come from SELLING DATA, not selling consulting projects. So it is smarter, from a shareholder perspective, for the company to sell the data, rather than let CG leverage it to sell more and higher profile projects. Those are facts, not my opinion. Now that that is established, it'll be pretty easy to analyze why the firm is such garbage. CG is not important to the parent company. Hence, CG is not given the proper resources to operate effectively. This is why you see multiple reviews citing 'high turnover' and 'over-worked, under-appreciated' as well as 'pays significantly lower than competitors' (I can confirm all of those cons are very, very true). So without proper resources and management, the place is an absolute dumpster fire (I won't go into details but essentially everyone is at 200% capacity and hence stressed and miserable all the time; seniors take it out on juniors weekly) The only way this horrible place can be fixed is from a C-suite level, and that is absolutely not happening, would be surprised if this death-hole from hell is around by 2020. Oh one more thing...if you have a reputable MBA, DO NOT WORK HERE IT'S NOT FOR YOU!