I would make sure you hear those amps with the Harbeth's before you decide. Harbeth's seem to do better with solid state than with tubes. I tried a tube amp with my Harbeth Super HL5's and it just did not work well together. (ARC VS55, Quicksilver V4's)
I have heard the Cayin and the Rogue and they are both nice amps but I would not want to use them with the M30's. I would look at Primare and Musical Fidelity integrateds for those speakers. They sound great together. I went with a Musical Fidleity TriVista 300 (hybrid integrated) with the Super HL5's and they work very well together.
Good Luck!
I have heard the Cayin and the Rogue and they are both nice amps but I would not want to use them with the M30's. I would look at Primare and Musical Fidelity integrateds for those speakers. They sound great together. I went with a Musical Fidleity TriVista 300 (hybrid integrated) with the Super HL5's and they work very well together.
Good Luck!