what you wrote sounds about right and matches my experience with them (never worked for them, but with them on clients, some colleagues went there).
Now to pick an analogy: If MBB are the Marines (who already consider themselves to be pretty tough and elite) - these guys consider themselves to be the Marine Scout Snipers, so the elite of the elite. And from what I have seen and heard, they usually deliver on that promise.
You can also take the military analogy even further:
- Working with MBB may be to many "normal jobs" what Marine basic training is to a wellness yoga retreat. Then working with Alix Partners is like Sniper School - dirtier, tougher and even more demanding.
- But then so are the missions they are called in for. There are some missions where you deploy the Marines, and some for which you may need to go even beyond that...
Hope this helps.