Top 10 rankings: No. 9 for retention This Chicago-based jobs website and staffing firm invests heavily in its IT employees in an effort to gain a competitive advantage in a fast-changing marketplace. Regularly scheduled "think days" allow employees to explore technologies beyond the scope of their regular jobs, and quarterly 24-hour hack-a-thons encourage collaboration and innovation. And tech workers are given "spring cleaning" days once a month to clean up dead code. Perks include flexible work arrangements, a casual dress code, reimbursement for training expenses, half-day summer Fridays and all-expenses-paid company trips.