The work-life balance is a hard part of the job. The expectation is that you will be working 10-12 hour days with little return at first. Luckily, there is a great group of people you get to work with everyday so that you still get to work in a fun environment, but be prepared to miss outside social obligations for a while.
I think this depends on the office you work in because they all may have slightly different cultures. At the office I worked in, longer hours were often expected or come with the territory of the job due to after work events. This was a few years ago though and I know TEKsystems is working to change their work life balance by adding work from home or flexible scheduling options for Account Managers and Recruiters who are above their growth line. Overall this is a highly commissioned sales job and you can decide to work as much or as little as you want to be successful but it may be difficult to be very successful in the beginning (earn a high commission) by working only 40 hours per week. I think I typically worked about 55 hours per week.