Pros
Presents glossy image of a serious technical recruiting company. I worked with TEKsystems off and on for many years and used to hold this company in high esteem. A few recruiters I worked with had been there long enough to know something (but that was years ago). Hourly rate is fair.
Cons
Hopefully you have a spouse with good medical plan. Once placed at a client site, you're on your own; young, inexperienced account managers seem sincere enough initially, but don't know anything about industry nor how to treat seasoned professionals turned consultants. You're merely a seat-filler and paycheck to them, so pray nothing unexpected happens in your life -- the only time you'll hear from your AM is if the client company has an issue with your misfortune. Then they become disrespectful, unfair, basically treat you like a dog since you've (unintentionally) messed with their revenue stream -- have no doubt that's all that matters to these kids. Don't count on HR, they're rendered worthless.