@dweller , I haven't. It did help when I turned the power up but thought to myself why do that when the power is cut in half for Triode and then I just turn it up? I'm sure I'm missing something. I'm only about 19 mos into this journey (recently anyway). That said, I like Ultralinear so much anyway I haven't really tried Triode that much.
@brighamdoc , it sounds like you are going through something similar I had with the M3s and my search led me to Volti and I couldn't be happier. I had considered Cornwall IVs but never heard them or the other speakers you listed. The X4s may do the trick also but most, including me, find you need a well treated room with them - just fyi. Also the break-in isn't complete until around 400 hours - but sound better at 100 and again around 200-ish. I'm glad I went used w/ my Rivals as they are broken in already. I hope a used set comes up for sale for you.