For other readers, RME steadyclock is very good at jitter rejection. So you only need an external master clock device when you physically need it, in other words, when it is practical. As long as you can get it synced up with adat and spdif cables  and suplied WC connectors on the gear itself all is fine. Better see it as clock distribution. Sometimes a central clock is more practical in a big studio, but it is never to increase audio quality. Degradation of audio quality because of external clocking can happen, but is not a result of the sending clock but at the receiving device (if it is a poor or cheap design) and there is nothing you can do about that, not even sending a perfect clock if that were possible.