Hi lollipopguild, thanks for the reply.
It seems from your experience, the ER is better than the IsoCat7.
In fact, I had the dcBL-cat7 cable for a short while, before I managed to get the Cat7u cable and the iso-cat7 as a set. Comparing the Cat7 cable alone, versus the Cat7u and IsoCat7, there is a big improvement in smoothness and imagining. Things seem more holographic. I will try to put the IsoCat7 ahead of the cable and see what happens.
Certainly the ER is a tempting option! Do the external clock make a big difference to the ER?