KT88 in Rogue ST-100 amplifier

yes, a real downer that made me appreciate the 120s.  
try them if you want to be disappointed.  
if you want to affect the sound swap the 12AU7 and 12AX7.  

What are you lacking with the KT120?  I much preferred Gold Lion KT88 when I had a Primaluna integrated over the KT120 but that's a different circuit. The KT120 were very powerful and dynamic but lacked in midrange richness. Very analytical and almost strident. They didn't last long. However,  they may be the best tube for your amp if Rogue designed the amp around that tube. 

I was trying to get some feedback here to determine if I’m missing anything. Looks like the answer is no. I did swap 12au7 and 12ax7 with good results. 

What did you swap the 12au7 and 12ax7 tubes to? What changes did you hear? Thanks.

Gold Lion - more refined and relaxed presentation than the stock JJs. More open, better soundstage. 
Brimar 12AU7 (combined with GL 12ax7) - more extentended, more texture in the bass. Smooth and sweet up top. RCA Cleartop 12au7 (combined with GL 12ax7) - more top end extension, slightly more relaxed mids, tighter bass.