I definitely like the options having a Pass Preamp with the Sit-4…maybe it’s me but having separates is really nice…the Sit-4 really sounds nice with my horn speakers. I had a lot of tube gear in the past with lots of problems with the Primaluna gear. I always missed tubes so just yesterday I put in the Modwright Analog Bridge and it definitely changed the tone for the better, I slammed all the most harsh sounding fingers on a chalkboard electronic music through it and wow it took enough of that harshness away so I didn’t leave the room..one song I love is from Duran Duran Ordinary World it took that song and gave it a nice sweet tone..
I also have the XA-25, love the Sit-4 more…if you have to go all tubes play it safe and get the Cary Audio SLP-80…