I've had the R10P for about nine days now, but decided to return them to Hifiman this afternoon. After 50 hours of listening or so I just didn't think it was a good fit for my listening preferences, and decided to get the Susvara instead. Some impressions below:
This is not surprising since Susvara have become the benchmark for high-end headphones. And which version are you getting, the old or the unveiled?
As for the HE-R10P, I don't understand your comments. Similar to the Audivina, these headphones have a relaxed sound signature. Moreover, a huge soundstage comes at the expense of channel balance (you feel sometimes missing a sweet spot, but not that much imo), which some people like, others don't. I bought the Audivina's and fell in love with them despite my D8000 Pro, which is a highly regarded open-back that competes directly with the older version Susvara.
Also, I tried the albums you mentioned, sorry, the ones you didn't like on the HE-R10P are actually, in my humble opinion, low-fi albums. Some metal thrash and Wham? You're kidding, Wham sounds dull and dreary even on my 20k front-end, I call it great music, poorly recorded. I see you also got the HE6SE v2's, which I had too before the right driver died, and all I can say is that Audivina are better headphones overall, my daughter (young ears hear better) told me my HE6SE v2's were lean and thin sounding in comparison. Mind this, HE6SE v2 are damn the fastest sounding headphones I heard, the pace & rhytm are only second to Susvara. Anyway, assuming the HE-R10P's are better than the Audivina's, I don't see how they can be inferior to the HE6SE v2's or be so bad generally?
PS: Susvara is a completely different league, so I would not compare it to anything. Still, Susvara isn't as versatile (in terms of genres) as some others, so I settled on the D8000 Pro, which does 85% of what Susvara does, but is overall a more versatile headphone. That being said I love Susvara a lot and to-date I did not hear another headphone which could beat Susvara.
So, if you like the Susvara sound, just buy it, because there is no other headphone like Susvara imo.