The metal faceplates on the earcups are removable and V-Moda has plenty of designs to choose from in its online store (yes, they cost extra). It's a little tedious to remove and refasten the faceplate's six screws, but when tightened, they definitely keep the faceplates on the headphones.
Lastly, each earcup has an input and you can daisy chain headphones with a friend (you can both listen to the same music) or mix two inputs. A "V-cork" cap is included to seal off and protect the unused input.
When unfolded, the XS may look like a clone of the old Crossfade M-80, but the sound has evolved. The XS' sound is more neutral and natural and takes the edge off harsh sounding recordings. At the same time resolution of fine detail is still quite good.
In short, the XS maintains just enough of V-Moda's weightier bass sound signature to keep the company's fans satisfied, but the XS should appeal to more audiophiles than the older model.
With Holly Cole's "Temptation" album, the prominent acoustic bass lines have more depth and body than what we heard from the M-80. Cole's vocals also benefited from the change to the XS; she sounded more natural and less canned over the XS.
We also compared the XS to V-Moda's over-the-ear M-100, which sounded like a much bigger headphone. The tonal balance tilt is weightier, fuller and rounder. Also, the soundstage on the M100 is bigger. But at the same time, the M-100 is a more laid back headphone than the XS, which is more forward sounding, with a little bit better detail. We liked both, but in some ways preferred the XS' fresher, more immediate sound.
To finish up we compared the XS with one of the best sounding on-ears on the market, the Beyerdynamic T 51 p ($289). That headphone is even warmer and richer sounding than the XS, its bass definition is better, and it's more see-through transparent. You hear details, like a guitarist's fingers sliding across the strings more clearly over the T 51 p. The XS blurs the subtle details, just a bit.
On-ear headphones offer the advantage of being more compact than over-the-ear the models and potentially better suited for mobile use. But finding a good pair of on-ears isn't so easy. They're a bit of a rare breed, though the number of recommendable models is increasing.
The V-Moda XS qualifies as one of the excellent ones. It's very well built, relatively comfortable to wear, and offers strong performance for a headphone in the $150-$200 price range. That it has a minimal gap between the headband and your temples is an appealing trait, though not everybody minds the gap so much. In our book, it's just as important, if not more, that the headphone folds up into a compact case that's easy to tote around.
Editors' note (June 13, 2014): The rating on this product has been updated to reflect changes in the competitive marketplace.