Their interview "gauntlet" consists of 5 or 6 hour-long chats about their employee-owned, pseudo-MLM business model. They never gave any useful details about the role I might fill or the solutions they specialize in, or really dug into my technical qualifications at all. There is no proper case interview or structured technical exercise. I speculate that you're largely there to feed your interviewers' internal performance metrics centered on "recruiting" and conducting rote interviews.
I came away with the impression that SEI over-charges clients to offer management consulting's low-hanging fruit... sketch a solution, but don't implement it; offer recommendations, but don't operationalize them; map process inefficiencies, but don't change them.
If the salaries are accurate, SEI may be worth rolling the dice on... but expect undue emphasis on cultural fit and what client/work you might bring with you.