I am using Translation Office 3000 and can recommend it to every translator. It is a very good tool, keeps track of all your clients, jobs, invoices and payments. I especially like the fact that invoice templates can be fully customized. However, since everyone has different needs and requirements, I suggest you simply download the trial from their website and try it for yourself. Before I actually bought a license I asked them to add a feature. Two days later, a new version was available on their homepage and the feature I requested was there.