I have a Hegel H-30 paired with a VAC tubed pre amp; and love the combination; great sonic density; sound stage, details, fast and accurate. Very good low end; and crystal clear high's. I listen to jazz, vocals, some popular groups; and little to classical. It works well on all genres. I've not had a tubed amp, but perhaps this way you can get the magic of tubes; and the power and reliability of great power amp. Drives any load; I have one amp; running it as stereo unit. Not heard the H-20 or H4.
Good luck, hope my thoughts are useful
Good luck, hope my thoughts are useful