Well, I picked up Sony's PFR-V1 from amazon after getting a gift certificate for xmas and some rebate checks. First though some background you're free to skip over.
About 2 years ago I signed up on this forum before a trip to Japan, looking for suggestions of cans to pick up over there that might be more expensive or unavailable in the states. I was originally going to get A/AD700s, but saw they were cheaper in the US. I ultimately ended up with the JVC-Victor HP-M1000s. They've been wonderful at keeping a smile on my face. Good enough to the point where i haven't wanted to upgrade them in those two years (which speaks to their quality in my opinion haha). However I recently decided i wanted to try some open cans, and get some soundstage. I was looking at the AD700s again, but hearing about their lacking bass kept me away (as I listen to a lot of dubstep, dance, and some trance). Anyways, I remembered the v1s when I was in vacation in japan and searched amazon to see if any were available used. I was amazed to see they were under $200 (when they were about 55,000yen when I saw them at BIC camera two years ago) I didn't remember caring for how they sounded, but I was in a busy, loud department store and figured i was wearing them wrong, so i pulled the trigger and got them. (turns out I was wearing them backwards, when i first got them I put them on, thought they were still uncomfortable, then looked at the labeling on the headband lol)
anyways, onto impressions.
-First, these were packaged very nicely in the box. The box had that nice matte printing that nicer electronics seem to come in. inside the leatherette case is wrapped in a foam sheet. the cans are nicely tucked into this pouch. in the center is a felt pocket that holds the tiny portable booster amp (2 AAA powered), and extension cable, and a 3.5 to 1/4" adapter
-adjustment is a bit of a pain, as it's a lot more picky than your typical pair of headphones. I also had some difficulty in getting the ear tubes to seat in my ears well, but they're fine now what i've finally got both height points set. The coldness of the tubes in your ears is a bit strange at first, but you nearly forget they're on once they warm up.
-I first tried them out of the headphone out on my laptop, using the booster. The first thing you notice is the airiness, how the music seems to surround you rather than play from within your head.
-I later plugged them into my little dot I+ amp. These aren't really portable headphones, so they've been mostly plugged into this amp. I'm sure a solid state amp would be better, but this hybrid unit has sufficed.
-every level is very detailed and controlled in my opinion.
-highs: the highs are accentuated by the openness and the lack of bass. It can get a little shrill and irritating on some songs, maybe a little too forward.
-mids: a good strength with this set. instruments are detailed and well separated. upper mids though can get grating with the highs.
-bass: accurate, and it extends pretty far, but very recessed and dominated by the mids. It could be that i'm used to my JVC-Victors, but they lack any sort of punch or boom. This isn't entirely surprising given the design.
-soundstage: The real strength of these headphones. The open-ness and instrument separation really makes you forget you're wearing headphones. It's not quite like having bookshelf speakers going, but it's much closer than any other headphones i've tried.
Now, after listening to the PFR-V1s for a couple hours i decided to throw my M1000s back on. A completely different animal. Instruments aren't as well separated, the highs are on the recessed side, and the bass is supreme. The bass is less detailed and controlled, but it doesn't overpower the rest of the spectrum. Much warmer and a little more fun in a way. This is what I wanted though, I wanted a set of headphones completely different from my M1000s to complement them.
I wasn't sure if i'd be keeping these Sonys when i first purchased them, but I'm very happy with them. Their sound is very unique, exact, and airy (to me, I haven't had experience with many high end open cans, so i can't make any comparisons there). At the current prices they're a solid buy in my humble, unexperienced opinion.