I received the Royal Princess tubes. Right out of the box there was a noticeable reduction in hum from my speakers, enough that it is nearly negligible, I would say less that my Stereomour with the JJ 2a3.
These tubes were used previously, reportedly with less than 400 hours on them, I don't know when they were last used. They did not blow me away (other than the low noise floor) initially so I let them play about 5 hours and listened again, much better, noticeably better than the EH but not a night and day difference. I put on The High Kings "The Parting Glass", fantastic sound enveloping my room. Great tone. I'll put a few more hours on them before passing judgement.
Best,
Ed