Just got mine today, and thought I'd share my impressions. Notes: I'm running these from a uDAC-2, and my other good pair of headphones is the KRK KNS-8400. As with everything, YMMV.
Aesthetics
Game's over, everyone else. These are the most beautiful pair of headphones I've ever had the pleasure of holding/using/seeing. I think this is the first time I've said "Wow" upon opening a box of headphones:). Finally, a $300 pair of headphones that justify the cost in terms of aesthetics. Just look at 'em! They've got a good weight to them, and cup rotation is smooth (they can lie flat). No shakiness or creaking.
Comfort
On a comfort level of 1-10 (1: SR225s/V6s, 10: K601s), I'd probably put them at 7.5 or 8. The earcushions are plenty deep, and not huge, but fit my ears fine. They're a little stiff, and have a bit of clamp, but it's not too bad. The headband is probably the least comfortable part. It's not terrible, but you definitely feel it. There's not much padding, and I've done some small adjustments to how they sit on my head in the hour+ I've worn them.
Sound
Fantastic, in a word. When compared to my 8400s, they're definitely bass heavier, in terms of both warmth an impact. I wouldn't consider them to be neutral. But while the 8400s are probably slightly more accurate, they can sound a bit lean at times, and the treble can get a bit hot. Not so with the L1s. They are the epitome of listening enjoyment. If you want to monitor or mix or listen critically, you can get the 8400s. If you want to enjoy the crap out of your music, get the L1s. They are warmer than neutral, but it doesn't detract from the rest of the spectrum; it merely enhances the enjoyability factor. I always kind of wanted a bit more impact with my 8400s, and these deliver. But again, the bass is well controlled and tight, and doesn't crash the midrange and treble party. They are quite smooth and non-fatiguing; very nice, but I probably wouldn't want any more smoothness. High frequencies are well extended, and everything is presented well.
One interesting thing I've found is the way the music is presented. They have an excellent soundstage, and everything is blended together. Not in the sense of being muddy or undetailed, but rather, you're enveloped in sound, and it's just very pleasurable. From what I can remember from all the headphones I've tried, their signature is unique. They sound as though you've got a bunch of speakers around your room, not two drivers right on your ears. Again, very nice.
Summary:
I've tried a lot of headphones in the past four or five years, and I didn't consider some of them to be worth MSRP. My equipment may not have been appropriate for all of them, but I have not been as thoroughly impressed with any as I have been with these. The whole package (aesthetics, comfort to an extent, and sound quality) makes me think that this is one of the few, if any, headphones with which I'd be perfectly fine paying MSRP. I only hope that they get some more attention with the Beats and Bose crowd on the Apple Store's website, because they're definitely worth it. It would take me less than a heartbeat to prefer spending $300 for these over spending $300 for Beats.
If you can find these, buy them. They're excellent all-rounders, as Ultrazino said. If you have the means, I highly recommend them.
Still interested in if anyone else shares this opinion on amping.
