So it's the others that are too bright and not the O2's that are too dark.
I think the BHSE has better details and dynamics than the Aristaeus. It also seems more transparent to the source material.
When tubed with GEC KT77, the BHSE can be a good match with the HE90. Still not as much smoothness as the Aristaeus, perhaps, but it has better details and dynamics.
I wonder about the WES vs. Aristaeus using the HE90, maybe the upcoming CanJam will have some impressions.
How do the O2 mk 1s sound with the KT77s? Did the BHSE have to be rebiased to handle those? I have always wondered about using those tubes with the BHSE. I thought KT77s was a significant improvement over most EL34s in Marantz Model 9s in the 1970s.