Thanks for the listening updates guys. I've been on the fence with the 6G. My only problem was the talk about the battery issues. I think I'll buy it locally just in case I need to do an exchange.
My plan remains to pair the Nano with my Pico Slim for use with IEMs mainly but anything low impedance. I was considering selling the Slim and keeping my SR-71A but that got reversed after I did extensive listening with IEMs, W3 mainly. I wanted to thin my collection but there was no contest after I did serious comparisons with only IEMs recently which I'd never done before . I really don't need a super-powerful portable amp anymore and I'll be keeping my XM5 which is no slouch.
Today I was listening to my Orange shuffle (with KSC-75) which is 4 years old I think...I heard a never before "POP" sound. UH-OH. I was hoping the battery just died but trying to sync to my PC, it is really dead. And I was just praising it for lasting so long, which it did and through extreme conditions. A pic from Feb. 2007: http://inlinethumb27.webshots.com/27418/2229885410044175878S600x600Q85.jpg
...so, this sudden death in the family gives me a good excuse to pull the trigger. I do still have a Blue shuffle from 2 years ago. I just received a pair of Yuin G2 from HeadRoom today to compare to KSC-75 for use on my job. G2 sounds nice, with less bass for sure. Overall cleaner sound though.