I really enjoy the Stratus now. It has well over 100 hrs on the NOS tubes, and it sounds wonderfully clear, quiet, natural, and alive with presence. The HE-6 is still burning in - some have said it needs 300 hrs to reach full potential, and I'm willing to believe that. It keeps improving every day.
The real joy today is that my T1 has returned from repair at DHC. It had really opened up after about 300 hrs, and before the cable adapter developed a crack, it had become my favorite headphone using a DHC RS copper Complement balanced cable with the Rudistor RP010B "quad-mono" ss amp.
So I compared it on the Stratus, and the Stratus produces all of the inner detail and natural timbre, with the added dollop of presence, of goose-bump "you are there" feeling on every note, from every voice. As santacore said, rich, full, fast and powerful, without a hint of bloom or overhang, very satisfying, gorgeous music.
and it's not fully burned in yet.
The HE-6 has a long way to go. I'd say the T1 is working the very best on the Stratus right now.
For my ears.
PS - oh, yeah, Sweden, the OTL comparison. I have a nice 421A OTL in the cupboard, and I owned the EC Zana Deux for a while. Very fast and clean, but not one iota of real presence with headphones. With speakers, an OTL can work magic - I have the Joule Electra VZN-80 OTL driving my big speakers, and I love the sound. Tons of reactance in the motors. But not with headphones.