Pros
Potential (keyword) to earn very good commissions and bonuses. Good place to learn recruiting and sales basics. They have a sales/recruiting formula that many staffing agencies copy (for better or for worse).
Cons
TEK is a business, don't fall into the trap of believing it is a "family" no matter what they say. Also, educate yourself on TEK's non-compete policy. While not enforcable in many states, TEK is known to use its lawyers to intimidate former employees and the companies that hire them. The non-compete also restricts the communication you can have with the friends you made while with TEK. The non-compete also forces you to give up any of the social networking contacts you make while working for TEK. As someone who lasted 9+ years, I can tell you that burn-out is common. From a recruiter standpoint, TEK is the Enterprise Rent-A-Car of staffing companies. They will work you until you quit, and then find some other kid right out of school to replace you.