I co-operate with some translation agencies from time to time. They provide their employees with CAT tools such as SDL Trados and QA tools such as Verifica. I am not a master of using them, but I know the basics, that are enough to do the task.
My experience is that CAT tools slow down translation process, sometimes make it really challenging if some extra skills are required (like using tags), they may cause the decreasing of the rate (the customer sees the quantity of words that are repeated and usually provides lower translation rates for them), but they are good for following the glossary and then really helpful for editors. If the text is very formal, with complicated technical slang, using CAT tools is reasonable.
