Especially in uncertain economic times, it’s critical to find out what other translators are saying about prospective clients before you take on work from them. In addition, even those of us who make a standard practice of checking an agency’s payment ratings before accepting work need to add an additional step: re-checking the ratings for an agency that we haven’t heard from in a while (don’t ask me how I know this!). It’s important to remember that an agency’s fortunes can change over time, and that word of this normally surfaces on agency rating lists fairly quickly.
About Translation has an excellent post on agency rating lists including the subscription fees for the well-known services. The important thing isn’t so much which list you choose to join, but that you always check it before accepting work from a new client, or before accepting repeat work from a client that you work for on an irregular basis.