My plan is to only listen with the H20 (with stock opamps) for a few days, and then do more direct comparisons with the Jotunheim, and maybe the micro iDSD, though at least with single ended outs those two seem to sound quite similar.
So far my impression is a vastly improved sound stage in that I am perceiving a lot more depth than I'm used to. I could simply misremember, though. Too bad the Yggy doesn't have two XLR outs, that would help with proper A/Bing.
The H20 sounds very detailed. The highs are a bit strident, though - so far.
Bass seems every bit as good as on the Jotunheim, if not better.
A few times it also sounded like something was briefly discharging, maybe (short pops). Maybe something needs to settle in, I have no clue.
This thing has insane amounts of power. It's plenty loud at 7:30 even on low gain. I'm using the 4-pin XLR out with my Ether C Flow right now, with Yggy balanced in. As has been mentioned before, the three gain levels seem a bit useless, as there's hardly any difference between them. The difference between the Jotunheim's two gain settings is much bigger than between the lowest and highest in the H20. Maybe that's different with the other outputs, I have yet to try those (and I don't have a headphone cable for the two 3-pin XLR outs). The volume cuts out relatively soon when turning the knob to its lowest setting, in that it could theoretically get a lot quieter before it mutes the output completely. On the bright side, I'm not noticing any channel imbalance, while the Jotunheim has some at very low volumes (much lower than I would ever use).
The volume knob is big and smooth, feels better than the Jotunheim's. Its volume indicator is not at all visible from where I sitting, because it's on the base of the knob, which is covered by the top from this angle. That's a silly design choice. The case is a fingerprint magnet, but it looks nice.
I'm definitely tempted to try the SS3602s right now, but this is plenty good for the next few days.