So its been a solid 11 days+ with the ie80 and I'm now fully confident that they were worth the extra cash over my Vsonic GR07 Mk2.
On the plane back from Toronto they isolation was great, you could still hear ambient plane noise but it was deadened considerably. I was blown away by how good a few songs I listened to sounded, most especially Gotye's Somebody that I used to know track. Everything is clear and the instruments, all of them, are perfectly realised. I felt the hairs on my neck stand up as the chorus came through. There is no distortion at high volume either and the bass goes lower than the Vsonic but you get that Sennheiser soundstage thrown in.
Very expensive but if up must have one of the best sounding earphones without going custom iem then these are just the ticket.