People don't usually like them because it is another link in the chain but if they have the transparency they can be very beneficial to lift a dull recording or even help with issues due to room interaction with your equiptment. As I do a lot of recording and CD production it is invaluable as part of my regime before burning. They are also very helpful in toning down anomalies with old recordings. I know some people will poo poo the idea of using them but barely one recording is produced without them nowadays.