Pros
You can make a decent rate and get some experience on your resume.
Cons
OMG, they lie. Most of the time when their recruiters call you they don't have a job, even if they say they do. They data-mine you for as much information as they can get. I have caught them more than once saying that they have a position they're recruiting for - and they don't. Tips - never, ever tell then how much you are making or have made in the past. When they keep asking (and they will) tell then you signed a non-disclosure agreement and can't disclose that information. Never tell them how much you want - make them tell you what the rate is for a given position, if they claim to have one. If they're calling you about a position, chances are good that other agencies in the same area will call you also for that same position. Don't commit with TEK unless it's your only option. Don't give them your references unless you know that TEK is submitting you to a client. They WILL call your references and try to data-mine them. Be careful giving TEK info like your manager's name, title, etc. Getting this info is often the only reason TEK is talking to you. I've worked in IT for decades and out of all the agencies, TEK is one of the worst.