Austin, sounds like you have the same problem with the Amperiors that I had with the HD 25-1.
I've only owned a handful of on-ears, but the Senn PX-100ii was one that left a good impression. No isolation though.

The M80's isolate better for me. I couldn't get a good seal with the LP/M100 as I need some swivel to get the cups to conform to my head. There's those new XL pads though which might make a difference.

Valentine, anymore preliminary impressions on the XS? How's the comfort for you, did you had a chance to check it long term?

Ergonomic Impressions: My V-Moda XS came in yesterday at around 12:00 noon central time. I used them from 12:30 to around 10:30 pm. These are the single most comfortable supraaural headphone I've ever used, and are up there with the most comfortable headphone I've used period (that includes the Paradox w/ Suspension Headband). I only took them off to eat and to watch this past week's Cosmos episode with my wife. Most of that listening was from my desktop rig (ALAC/FLAC files > JMRC > USB to ODAC > UHA-6S.MKII > XS). I did spend about 45 minutes walking outside to the bank and drugstore to pick up a few things as well.

It only took around 4 minutes to find my optimal fit - which was 3 clicks down for me, but YMMV. The odd part about the XS is that they don't *feel* secure, but they are. With most on-ear phones, the headphones are secured by the force of the on ear clamp. In this case, there is very little clamping force because of the redesigned Steelflex headband. Most of the force is carried by the far larger contact area between your head and the surface of the band, leaving the earpads free to be as loose or as tight as you need them to be for seal and stabilization only.

I don't have enough accolades for the design of these things. They are light enough to keep around your neck while on the go and not feel encumbered or impeded in the least. They isolate exactly the same as the old M-80s - which means not very well. They still have the same bass vents from before. For me, this is a plus as I don't want to get run over by a car navigated by some Chicago driver on a smartphone.

Re: Sound: The XS are still new and I don't want to let "new toy" bias overcome my better judgment. So, normally, I wouldn't say much at this point. I usually take around 3 weeks or so to make a final judgement on a new piece of gear. But, since you're making a buying decision soon and I have a few minutes, here is what I've got on my notes from yesterday's listening.

Playlist (in order of listening, a few tracks on each with the exception of Moondance and One Nil which were full album listens. Included because headphone tastes are often genre specific.): Bon Iver - For Emma, Forever Ago & Bon Iver; Van Morrison, Moondance; The Outfield, Play Deep; The Who, My Generation/Best Of & Quadrophenia; Bob Dylan, Bringing It All Back Home & Highway 61 Revisited; Athlete, Tourist; Modest Mouse, We Were Dead...; Paul Simon, Graceland; Gin Blossoms, New Miserable Experience & Congratulations I'm Sorry; George Harrison, Let It Roll; The Beatles, Help! & Let It Be; Jim Croce, The Way We Used To Be; Neil Finn, One Nil; Sixto Rodriguez, Cold Fact & Coming From Reality; Leonard Cohen, Songs of Love and Hate.

To my ears they are a substantial improvement over the M-80, especially in treble extension, bass evenness and bass tightness. If anything, I think that the two hype threads on the other site are undervaluing the sonic differences - seeing them more as a shrunken, clikfold M-80. I think - or at least certainly hope - that future measurements will bear out the improvements I'm hearing here. If it doesn't, well, then I shouldn't quit my day job 

The XS's treble response extends higher than its predecessor without becoming unduly bright or piercing. Cymbals and strings hav e the appropriate sparkle, while still lacking the expected bit of top end air. That's such a general statement that you can say it for most headphones, so put another way: the treble on the XS doesn't sound shelved like it did on the M-80. Despite the better extended highs, the XS retains the M-80's pleasant character. It's still a slightly warm headphone. Moreover, harmonicas and trumpets don't gain extra harshness. There is no added vocal sibilance, which to me is still the great crime of the HD25 and Amperior. My go-to test album for sibilance is Rodriguez's Coming From Reality, where the song "Cause" sounds like it was recorded with a backing orchestra of tearing paper. On any headphone that adds sibilance, that song becomes a torture device. On the XS, that track is still listenable.

Most of the time, the XS's bass output felt extremely even and well balanced.  When measured, I don't think that the XS is going to seem particularly bass elevated in its frequency response. But, at times, certain tracks felt more bassy than I thought that they should. (In particular, in the opening bass notes on Paul Simon's "Graceland" and the bassline in Van Morrison's "Glad Tidings"). I switched back and forth to my Paradox, which I think makes a great palate cleanser, and even though the tracks sounded less bassy on the Paradox it wasn't immediately apparently to me why that was. Probably because I'm just so new to this, and most people would have figured this out faster. I didn't figure it out until I listened to The Who's "Baba O' Reilly": the synthesizer track, which sweeps back and forth, felt more narrow on the XS than it did on the Paradox. When I went back to the curious bass tracks and compared them again, it was clear: the XS's imaging/soundstage seemed taller than it was wide and my narrower perception of space on the XS made the bass stand out more.

The above might sound particularly negative, like I'm pointing out some sort of flaw in the XS. But keep in mind that this is a closed supra-aural headphone. It's been my experience that this type of headphone images poorly and even good ones tend to come off flat. The Amperior certainly does. Poor ones come off extremely muddled and confused. Given its headphone type, I found its ability to feel reasonably spacious pretty impressive.

As far as the mids: I rarely listen to purely instrumental music, so mids are important to me. The M-80s did mids very well and the XS continues to do mids very well. The upper mids might be a bit forward; I'll have to confirm that on further listening. If you look through my playlist, its indicative of my genre preferences and I think that the XS sounds very good with the type of rock music I've listened to on it thus far. Both vocal and instrument timbre sound natural and not artificial. Jim Croce and Paul Simon sound fantastic. Lisa Germano sounds ethereal while performing background vocals on Neil Finn's "Turn and Run" and "The Climber," as she should. Isaac Brock's syncopated vocals have all their appropriate squawk. Leonard Cohen's baritone stretches appropriately deep and sounds full on "Avalanche." Ringo Starr probably sounds better than he should on "Act Naturally." His drumstick tapping sounds great too. I plan on listening to some soul today, and I expect Sam Cooke to sound as great as he ought to.

TLDR: After a day of listening, these sound pretty damn good. I'd buy them over the DT1350, Amperior, HD25-II, and of course the original M-80s. Measurements are certainly needed to confirm this, but I think they sound much better than their predecessor. When you say you want a light, fashionable headphone that sounds good for on-the go-use (and works with the V-Moda boom mic) I think these are the headphones you want.

Thanks for the feedback.  I liked the M80, but they never sounded quite "right" to my ears.  Listening to Radiohead, for instance, was "fun" but just not the way I think Radiohead is "supposed" to sound.

Then I found the 1350s, fell in love, and haven't looked back.

I wonder if the XS would cause me to rethink things...