The ERRx is quite transparent, so amp choice is harder because you can hear the amps sound signature.  I like my ERRx paired with either my Odyssey Stratos or Nelson Pass amp both SS.  The amps are smoother sounding and gives it a richer midrange and and highs sound more natural.  

My other amp a Parasound 2125, makes the highs sound bit harsher and the mids a little thinner. I don't know if my parasound is more transparent and I am hearing the digital recording, but it doesn't as good as the other amps.  Best thing to do is probably try 2 - 3 amps and see which ones you like paired with the ERRx.  Maybe one of the Decware amps?

My Taboo I had did sound great with my ERRx speakers. My old Tori MKlll also sounded great as well as my ZMA (way more power than I need). I am currently using a Micro ZOTL2 made by Urban Audio and even though it's a 1 watt tube amp (actually a headphone amp like the taboo), it sounds like the best solid state ever because of its incredible speed. It's hard to believe a 1 watt amp can play loud but the ERRx are very efficient.