So, I've had the ET5 all of 24 hours and I'm already smitten. I was going to wait until I had the caps broken in, but...
While I'm aware of the "I have to like it 'cuz I bought it phenomenon," I have to say that even unbroken in, this preamp is a step above the ET3SE in imaging, bass texture and tone, soundstage, midrange detail, treble extension with less harshness, midrange/vocal "emotion"... etc. etc.
I can't imagine what it will sound like when it's broken in.