I got my HE-300's today and I think I can safely say i'm a big fan. When I opened the package I wasn't quite sure what to expect since this is my first experience with a Hifiman product. I must say I was pretty impressed. These cans are really great looking. I love the Hifiman style and had to snap a few pictures.
As to the sound I'm still getting used to it. I mentioned in the other thread (felt removal) that these sounded fantastic and I'm standing by that. I feel like as many have said, they have a slightly warm but still very clear and precise sound. If you do remove the felt it takes the detail resolving to a whole new level but I found it to be a bit fatiguing with poorly recorded music so they were quickly put back to stock. I'm unfortunately limited to my computers on-board sound card and my phone as sources right now. But even with these fairly poor sources the HE-300's sound amazing. They still manage to resolve details and bring out all the subtleties in the music while not becoming edgy or harsh. The bass is powerful but not overwhelming (such as my Sennheiser HD-439's with two ports open). My biggest criticism has got to be the cable. As others have mentioned the microphonics are atrocious. The cable seems to be of very good sonic quality but it is rather rigid and the hard plastic sheathing is what i think lends to the out of control microphonics. It very well could be that it's only a problem some would face but since i'm at my computer while listening when i move the cable rubs against my keyboard, desk, and clothes. Even the slightest brush against something is audible. I may see if I can find something to sheath the cable in to resolve this issue. Other than that I'm an extremely happy camper. I can't wait to upgrade the source and amplification components of the system. I'm sure they will only get better with better components.