Picked these up on friday and have since been listening to them, they are for sure a nice surprise!

My observations so far (please note that I have not listened to a whole lot of headphones, so YMMV):

• These do not seem to be the most resolving, but they also do not hype detail at all, so I'm not entirely sure they are not capable of more.
• The background is kinda grayish, which leads me to believe there are a bit of not-so-offensive resonances going on. There's absolutely no damping inside the cheap plastic cup.
• The cups are ultimately sealed by the earpad sleeves, so I put a round of electric tape just in case.
• The FR once you achieve a proper seal is fantastic, the bass strikes a very nice balance for the driver size, I also don't mind the 'recessed' upper midrange that much, in fact, most DF equalized headphones I find quite strident @ around 3 KHz. The 9KHz peak is not very bothersome, but I did EQ it down a bit. All in all very neutral sounding.
• The earpads are too stiff and a proper seal is very difficult for me to achieve (smallish noggin), the soundstage with the stock pads is also very flat and kinda meh, and the center image is weak.
• I tried rising the earpads using a pair of spare fostex pads stacked over and the soundstage improved very much in width, depth and focus. These are definitely held back by the mediocre pads.
• Isolation is kinda low but it could be improved upon with better pads and maybe some damping.

These are already quite enjoyable and useful for tuning my T50RPs. I'm also very eager to see how far can modding take these!

Edit: Earpads are 85-90mm in diameter, any replacement ideas are very welcome!

Addendum: These are going to get huge

More: Removing the back covers opens up the soundstage a bit and improves the high-frequency extension and overall clarity, while the tonal balance remains mostly unchanged. Purrin, if you're reading this, please measure with the lids off too!

Better earpads yield the most dramatic improvement without a doubt... still looking for a pair of decent 90mm pads, the taller the better.

I did unscrew the baffle to help remove the lids from the inside, ended up having to use a fair amount of force, however. Here's a gallery courtesy of Arve @ innerfidelity.

They should become widely available in pro-audio stores. These are decent portables since they are fairly efficient and sound great out of my Clip Zip, but will not isolate much unless you have a big head or get ahold of some proper earpads.

Seems like Fostex has some entry level HPS.  The Th5BB and the TH7.  Anyone heard anything of these?