Vantaggi
Too few and too incidental to name. At best, it is a steady paycheck until you find a more promising opportunity. Entry-level engineers can gain experience in technical endeavors, but any participation in marketing efforts is highly unlikely and even discouraged (but only implicitly, never explicitly).
Svantaggi
Extremely short-term, unsustainable thinking by management: micromanaging billable hours on a weekly basis at the expense of planning for long term growth. Executive level managers seem to have no clue how to incentivize or reward excellence, and they seem to have no understanding that work comes through getting to know clients on a personal level, not the reverse. Current management is leading the charge towards the complete commoditization of the engineering profession by always making decisions based solely on cost and never on value.