I bought this because I couldn't find edition 9s (if you've got one I'll buy from you).knowing it has the same driver, it does sound like an edition 9 in many ways. It is missing some of its clarity and impact and soundstage though.
As for ed8, Sig Pro is more enjoyable to listen to than edition 8s... but I find edition 8s to have more of a balanced sound across the spectrum. I find edition 8 more of an audiophile headphones, they're like really great speakers on your head. sig pro are warmer, both are very musical in their own way, as is the whole point of the ultrasone line...but right now I can't take sig pros off my head.
That's the first time I've read anyone say the Ed 8 are more balanced sounding than the Signature Pro.. In my experience its the exact opposite in terms of balanced sound. The Ed 8 have more bass and more treble, where the Sig Pros are more neutral in both spectrums. As far as enjoyability I preferred the SP since the Ed 8's treble sounded peaky and sibilant with electronic music.