They don't have the best reputation, and my guess is that sales aren't the best either. The older Denons cost more now used than they did new a year ago.
People's responses to the TH900 always surprised me considering how ridiculously bassy the FR graph is. Apparently it isn't super bassy despite the FR and sounds really quite nice. I'd love to see a teardown of the TH900 to see what parts they changed or "upgraded".
If you live outside europe you can PM the seller and ask for the VAT (local GB tax) excluded - they can sell it for £374 without that tax (about $600)
The 1 year warranty is pretty ridiculous imo. If im dropping over $1k on headphones, I dont want them going belly up after 14 months. The only reason I looked into these was because my d2000's have become unbalanced after 14 months of use.
I asked them; they don't ship outside Europe.