Since most of ANSER's work is in the government contracting space, it can be hard to feel like a part of the company sometimes. Working for a government client makes you feel like you are part of that team instead of ANSER. ANSER does try to do outreach, but it often feels like it encroaches on work (like having a team lunch that requires taking 2+ hours out of your workday, or having a happy hour that keeps you from getting home to your family as early as you'd like). It's a tricky problem to solve.
Finding out the requirements for getting a promotion or advancing can be difficult and require constant vigilance and following up on the employee's end. I once had to have regular meetings and follow-on sessions with my manager for almost a year to get a promotion, which only entailed a title change and about a 10% raise. The feeling I get is that nothing will come to you unless you ask, and when you ask, you have to ask repeatedly.
Promotion and advancement also stalls out at a certain point. If you start at ANSER early in your career, you may earn two or three promotions in the span of five years. But then you may need to wait another 7-10 years for your next promotion, and another decade after that. As mentioned before, the guidelines are not always transparent, and you can feel stuck after a while.
Although most of the benefits range between fine and excellent, parental leave is an example that is severely lacking. It had been a whopping two weeks for a long time, and ANSER made a big deal out of increasing it to three weeks a couple of years ago. It can be supplemented in some other ways from my understanding, but it is pretty weak. I have really enjoyed working at ANSER, but if I were to leave, the parental leave benefits and the lack of upward mobility at a certain point would be the key reasons why.