Pros
You have chance to work with smart people on real problems in a wide variety of domains. By consulting, you usually work on interesting problems, rather than legacy or maintenance, and have hand directly helping clients solve problems. Additionally, Def Method does have a strong focus on the happiness of its developers. They work hard to find engagements that are in line with the interests, abilities, and ambitions of their developers.
Cons
Def Method is not immune to the problems of other consultancies. Clients are usually the major factor in determining the quality of life at work. There have been engagements that have been more trying than others, though management endeavors to give support and consideration to those on more difficult clients.