Tested the Protector single-ended with my TWag JH13s (sending in for recabling tomorrow). I can unambiguously say that this is the best I've ever heard any amp. Better than my D10, TTVJ Hybrid, iQube. It might be that I just prefer the RSA house sound more, but that was another reason I got this amp- to try out the RSA sound.
To my ears, the difference between this and my other amps is like the difference between my iPod and my Hifiman. The bass is very punchy and tight, and the mids and highs manage to be oh so sweet and refined. The combination of tight + smooth is unbelievably seductive. I might truly be at the end of my audio journey. I'm now perfectly satisfied.
(PS, because I travel a lot, I will never consider a home amp).