"What amp should I look for if I like the power of the krell and the engaging sound of the pass?"
I also like the Pass very much, it is an extremely musical ss amp among the few ss amps I've heard that offers more than a bit of what tubes do well, sweet and open. Based on what you are asking for I would say the Berning fits the bill very nice. Low heat, dependable, long tube life, self-biasing, great bass, I mean this tube amp will hold its own against many ss amps out there in bass performance and exceeds virtually all I've heard in openness, this with a large variety of speakers.
The Joule is verrry nice but it is a more seductive sound and veers a bit away from neutral. I don't mean this in a negative way but I will say it doesn't have the liveness or present the dynamics shifts of music to the degree of the Berning but it may be more to your taste. It is very open sounding and separates instruments as well as anything I've ever heard. Massed vocals are magical with the Merlin/Joule combo. It will not sound like the Pass or Krell, the Berning would be closer in that regard. If your budget can swing it, I don't believe you will find a better match for your dollars than the zh-270 all things considered but listen to a Joule first, you may become smitten :^) On the other hand if you can't afford Joule just get a Berning and you'll be very happy, indeed!