Pros
Very engaging and interesting work. Projects are firmly focused on delivering real results, and you can easily see the impact you are having on the client businesses and on the individuals involved.
The people you work with are all smart and motivated, and the culture is very supportive - people go out of their way to coach and support others.
Firm management actively seeks feedback, and actually takes action to improve when this feedback is negative. This applies both to individual firm leaders and to organizational standards and procedures.
Pay is above average for the industry.
Kontras
You have very little control over your life - the North American practice is small enough that there is little ability to be staffed near your home city. Engagements also tend to start immediately after being sold, so there is little warning before you are asked to fly away to a remote mine site.
There is an expectation of willingness to work long weeks and long days. Engagements are often in remote locations that require long commutes to reach site. However, engagement leaders are typically very conscious of these demands and provide relief whenever possible.
Benefits (particularly health insurance in the U.S.) are not very competitive.