For years, I've stated a preference for the sound quality of the M3 speakers over the M22s. That certainly was the case for my 5 watt per channel SET tube amp.
My dad left me his Harman Kardon TA5000X. I had it recapped. The original Mullard 12ax7s were still excellent after all these years (not used very often). It puts out about 20 wpc.
So, I set it up in an extra room and compared the M22s to the M3s (no sub yet).
The M3s sounded excellent. BUT, the M22s definitely sound better! The bass is surprisingly strong, the mids are more open than the M3s and, of course, the highs sparkle.
Listened to some Kenny Rogers, Bill Evans, then some 88.1 KJAZZ, FM. I could live with this system!!
Love the M22s. I'll drag a HSU or two upstairs and that should put it over the top.
The Harman sound quality is not particularly tubey, it is clean top to bottom, rich and full sounding.
And, the tubes glow so nicely.