Body shop / not much about consulting - most of their work / or "projects" for consultants are secondment arrangements that are not really consulting work. Most of these arrangements just want a person to sit in certain roles without really requiring any technical skills. So if you are looking to specialize yourself / get the consulting experience then this is not the shop to head to.
Poor resource management - in very rare cases that you would be seconded to roles according to your current skillset. E.g.: it makes no sense to second someone with compliance background and nil IT skills / knowledge to an IT business analyst role. Most of the time they just send whoever is available on the bench.
Unfair performance management process - these issues are repeatedly mentioned in many other reviews. You nail appraisals / promotion opportunities / remuneration increment mostly by your amount of "internal contribution". One might say that this is very common across industries / firms, but the extent noted in here is just too much.
Limited client base - to be fair, they are trying hard to deal with this by diversifying the client-base. However, most employees only work for the-one-client. Thus, likely you would just be able to work and learn from one client.
There are many other issues (eg: issues at the top / politics) but I'd say the above are the most important ones to consider before you really want to join.