I interviewed with one of their Denver clients, was basically offered a job, but the Apex recruiter representing me lied and mis-represented me in the negotiation process, costing me the position. He straight-up lied about my hourly rate, raising it by 20%-30%, and further lied about my rate not being negotiable. It appears he did this in order to push his other clients.
If you are a tech contractor in Denver, I recommend staying far away and don't believe what you hear.
Additional con: obnoxious communication policies. They basically won't talk to you through anything less than a phone call, as if email isn't a thing. And their phone system makes it impossible to contact the person you're working with directly.