I have heard the ZYX R100 on Avid Diva and Acutus. I used to own a ZYX RS30-02 low output version and played it on my Verdier extensively on a variety of tonearms. The ZYX are a champ at bass and PRAT but it lacks a certain warmth and sweetness in mids and highs which is so very much required to enjoy rock. The ZYX is a reference to me for classical music and well recorded Jazz. The 4D is best of the lot for rock, I agree but that is expensive. I had a Denon 103pro prior to ZYX and I enjoyed Dire Straits more on the Denon than on the ZYX, just to give you an idea. The Shelter falls more in line with Denon. In fact it is supposed to be a default upgrade for Denon users/lovers. Hope that helps.
