Pros
As a consultant, each project will be an entirely different set of experience, from people, tools, and process perspective. You will be able to accrue experience rapidly. In addition, as you will be held accountable by both customers and your manager, learning to CYA and speak corporate lingo becomes second nature.
Cons
You will rarely get annual reviews. You will hardly ever see a raise. There is no 401k match; the fund choices are terrible. There are too many layers of management. Furthermore, your manager is not empowered to make any decisions on raises and benefits. He/she will actively avoid doing annual review as it becomes embarrassingly clear how little they can do for you. Your requests will be escalated to upper management and conveniently lost and/or delayed indefinitely. In the meantime, you will be told that your request is very important and please hold (cue elevator music). Any effected delay or hesitation on your part will yield just that little bit more revenue for the company, which is the only thing that matters.