Guys I'm at the Headphonium at T.H.E. Show in Newport and just heard something that I think might be able to compete with the ER4S. And it's from Noble of all companies. Let's just say I haven't liked anything they've ever done, and I strongly disagree with the secrecy they shroud over their development process.
All that aside, their yet-to-be-released earphone, the Savant, is dammed neutral, and extremely well balanced. On first listen I was reminded of the ER4S but with more bass. This is what I've been looking for, what everyone in this thread has been looking for, since we discovered the ER4S. Not to mention the Savant is extremely light and fits over the ear.
What's inside? Dynamic? BA? Both? Noble wouldn't say. He said they might be a hybrid, but would confirm nothing.
Before I rave anymore about it, it'd be awesome to get a second pair of experienced ears to check them out. They're aren't an incredibly deep fit like the ER4, so sound quality/neutrality might differ between ears more than we're used to in this thread.
If it means anything, Zack from ZMF Headphones also thought they sounded amazing, as good or better than the K10. (I don't at all like the K10, but there you have it).