Alex,
They've had focuser problems and are currently being ironed out.
I saw photographs taken with what I believe to be the 8" version. I'm not sure what camera was used to take them, but, man, it looks very, very promising. Flat field all the way across!
If you're interested, I'll chase it up and find out what configuration was used.
Bring on the Asian clones!
Regards,
Humayun