As with any firm, upward mobility is largely dictated by the luck of the engagement team/managers & partners you work with. Different Pods have different cultures. The rigidity of the Pod system often boxes out seniors from finding the best champions and mentorship opportunities for them in the firm. There are certain partners who can be extremely difficult to work for (micromanagement, confusing communication, constantly changing approaches midway through projects). This was ultimately the impetus for me leaving as I found another role with superior mentorship and partners who put me in a better position to be successful in my role.
Performance management is uneven depending on who your CC is. I was lucky to always have a great one. Often the performance roundtable meetings devolved into big gossip sessions with arbitrarily enforced performance criteria. It's very important to have managers who will stick up for you in these.