I'm finally getting familiar with the cool-looking little ES88 (now discontinued apparently). I thought that the cups would be metal. Well, those metal-looking legs connecting the cups to the headband are indeed metal, but the cups are disappointingly cheap plastic. The baffle on the driver's face is very rigid, that part is probably metal like on a number of AT models. It is comfortable, and I cannot get a proper seal, but whether I get a good seal or not does not affect the sound terribly as usually happens with closed-backs. Bass doesn't go AWOL as a result of a little bit less than perfect seal, either. I notice that the cups do not extend - instead, the cups swivel vertically to accommodate different size heads. It is mildly snug on my moderately large head. I bent the headband for a slightly tighter fit, and now I can use it as one of those sport headphones where the headband "floats" behind the head. Someone with a small head may need to bend the headband into more of an egg shape for best fit. AT doesn't avoid using metal backbones in their headbands, unlike some companies, so bending the headband won't hurt, or I would have broken mine already.
On a side note, this feels like what the iGrado headband should have been, relatively.
I like the sound, but it seems they didn't get the internal dampening quite right, it reminds me of how T50RP would sound at times when I used to experiment with one. "Overdamped" as another fellow somewhere put it6 may be the right descriptor. Otherwise, I like the sound, decent clarity and control throughout the spectrum, nice for the price. FR is like M50(x)'s when the stock pads are replaced with Brainwavz pads or HD280 pads: flat-ish mids and treble, boosted bass. The flat cable is practically a wet noodle. They won't be too hard to recable with some Mogami 2893 later.