Hi Ben,
I've got a Cooking Chef from right after they started being made in PRC. I've had no issues with the mixing function, but I finally gave up on the cooking component after it was repaired for the third time. It is a traditional Kenwood underneath, just made in China.
I've been curious about this as well, they've obviously standardised the design with Delonghi, now that the front PTO has changed, I'm not sure whether the new machines are essentially the old kenwood underneath with a new PTO or if its a cheap design in an expensive metal case. You can get an adaptor to use your slow speed outlet attachments from the late 700 series onwards.
Cheers
Nathan