Pros
I got recruited from the US - without a doubt, working at Newton turbo-charged my professional development compared to opportunities available to me in the States.
I worked on numerous projects, each of which presented a unique and challenging problem to solve; I got to work with some incredible individuals; all the while, I felt I had an amazing support network from my peers, my supervisors, and the upper management.
The culture is amazing, and you really get the sense that people care about you, your clients, and the company. There's also a work-hard-play-hard mentality, so everybody is a ton of fun to hang out with.
Cons
While my professional life was great, the consulting lifestyle naturally takes its toll on your social life. My situation was exacerbated by the fact I came from overseas and didn't have existing friends, so I could only really spend time getting to know my coworkers.
Additionally, the company is currently going through some growing pains as it becomes a larger business; however, nearly all of the issues are admin/strategic.