So, I had put on black filters and the sound is enjoyable but I always feel like I'm missing detail, so I was going to switch back to the grey, and decided to see how they sounded filter free. Whoa, treble. Cymbals especially. Bass goes really flat though. I wonder if thats more like what the ER4s sound like. It actually was entertaining with some newer pop stuff that has techno-ish sound and lots of panning and effects. Basically the complete opposite of how that music is usually heard (just bass, bass, bass). I've actually been surprised at some of the layering and background and other effects used in some pop music. Its definitely stuff that you don't notice (or in plenty of cases even hear due to poor equipment). I can understand why people recommend the SA5000 for techno/electronic.
Unfortunately it wasn't so good for other music. The greys retain most of that treble but you get back just enough of the bass slam, its unfortunately not a perfect in between though.
Oh, and I lost one of the ear guides so they don't wear quite as well (want to move around more). Still one of my favorite headphones. I am looking at moving on though, really want to try Westone 3s and then go from there. And playing the waiting game on a portable source (see how the 3rd gen Touch turns out and then decide between it and the new Zune).