I had the same feeling about my HE400 for a while. The trick is to NOT switch headphones in one session. Just stay with one HP, your ears will adjust and you should really start to hear and enjoy them. I pretty much went through the same thing when I got my HD700. Switching back and forth, I was ready to sell the HE400 on the spot. Just sticking to one HP for a session or even a few days lets you really appreciate them for what they are. Give it a try. YMMV.
I myself am in the process of doing this very thing. I got my HE-400 yesterday, and I'll give them a full week and a half or so before making a definitive decision. I'm a Grado fan (SR60i atm, may grab an RS2i in the future), so that is my point of reference.
These sound so utterly different from Grados. But, after acclimating the sound, there are some things I really have come to appreciate about the HE-400 over the Grados:
- The bass! Oh the flat, level, beautifully textured, full-yet-not-bloated bass! It's accuracy is just lovely to me. And this is coming from someone who considers themselves a treble-head and quite far from a bass-head.
- The smoothness of the upper mids! Now I fully understand the term "shouty" when people use it to describe Grados. Whereas Grados make male vocals peaky and edgy, vocals on the HE-400 sound utterly smooth and level. I have found that, on certain songs, I had become accustomed to mentally preparing for sharpness during specific parts while using the SR60i. Now, those parts come smooth and inviting on the HE-400, instead of sharp and intruding.
- The imaging! Everything sounds more correctly positioned, defined, and separated with the HE-400. The Grado SR60i sounds like a tossed salad of instruments by comparison.
But hey, even tossed salad can taste good with the right dressing, or in the case the right music selection. I find Grado still hits the pleasure button with rock and various rock-related genres. They have an energy and toe-tapping grooviness to them that can't be wrought with a more neutral headphone like the HE-400. I'll have to visit the local shop next weekend when I get a chance and compare the HE-400 head on to something a little more its own size - the RS2i.
I'm liking this HE-400, but not sure I'm "loving" it. I'm eager to compare it to the RS2i.