Pros
I've worked for, and worked with many well-known IT Consulting/Job-Placement companies in my 15 years in IT. Places like RHT, TekSystems, etc. KForce has treated me the best. I don't get pathetic, low-pay job offers or SPAM from uninformed arrogant recruiters who don't know I'm already in their system (yeah, looking at you Robert-Half). Any position I've done on behalf of KForce, good work has been rewarded with an increase in pay and benefits such as PTO. If work from from office isn't available, the recruiters will work with another KForce office to find me work. I am not mistreated by Project Managers or treated as a number (yeah, like you do TekSystems). And with permanent job placement, KForce still contacts me once in a while to see how I am doing at my new job to ensure I'm happy or perhaps how they can help. I am very pleased by how KForce treats us Contractors.
Cons
The only Con I can think of is that KForce is limited on some job placement, or companies they work with. They're definitely, unfortunately, not the first IT consulting firm that many well-known companies or organizations look to for contractors.