If you have a job opening or a high turn around rate like we do. (we are a staffing company) [CareerSiteBuilder] is a great place to to start. It is affordable and reaches hundreds of potential employees. When you search resumes sometimes when you enter keywords you have to play around with it to find the right phrasing. Its not difficult just time consuming.
Hiring Thing is great for new organizations just starting out with smaller talent teams. It is very simple to use, add users, walkthrough processes, communicate with candidates, and walk through the hiring process. It does not work as well when an organization grows, needs lots of open requisitions, and has a decentralized hiring process.