So did you pull the trigger on either? Anyway the ER4XR is here. Initial impressions - it is indeed a pretty good all-rounder. Enjoying it on its own, you'd be hard pressed to find anything wrong with it, especially if you already own an Ety. I'd place it as a step up from the 4P for folks who find the 4S too clean. But since we're comparing it with the iSines, or at least attempting to do so... Treble: The iSine 20 is noticeably more sibilant than any of the Etys. The 20's treble, while smoother and better controlled than the 10's & perfectly acceptable on its own, comes across as altogether too splashy next to the Etys. Mids: The XR sounds the most 'natural' and relaxed of the lot. The 20's mids are tighter with the groovy tips, giving it the impression of clarity. Not quite ER4S level, but it's a good try. With the older smooth tips... I wouldn't bother. Bass: Yes, that promised bass bump is there in the ER4XR. But it still doesn't hold a candle to either of the iSines and never will. And guess what? I actually prefer the bass of the ER4S to that of the XR atm. They are both very well extended (more so than the ER4P) but that extra bit of restraint in the 4S lets more detail through. Whereas the few extra db of bass in the XR strikes me as being there more to add a slab of warmth and butter to the sound.