When my friend and club member picked up his Zhumell Z10 OTA that he let me evaluate and test:
He dropped off his Orion XT8, 8" F6 OTA for similar care and feeding.
The mechanical quality and fit & finish are, IMO, on this sample, not quite on par with that of the Zhumell's, but certainly very serviceable and very good for the money. It required collimation tweaks of the secondary and primary but both went quickly.
Unfortunately the optical quality at full aperture was rather below par on this sample.
As the DPAC images at full aperture show, there is a significant turned edge with an overcorrected zone over the outer 70% to 80% of the surface. The surface is otherwise fairly smooth if a little lumpy in spots. The owner confirmed to me that the images with the scope were not really sharp at high power and focus is a bit vague. However, as this was his first scope he really had no other experience or point of reference to say the optics were sub par. I saw no signs of astigmatism, which is good and the fully illuminated FOV seems generous.
I then retested it with a 7" aperture stop over the front. This greatly improves the overall DPAC performance, though at the smaller aperture. The outer portion of the surface is still overcorrected a little but it covers less territory and, importantly, the turned edge is almost entirely eliminated. That overcorrected outer zone blends smoothly into a more neutral correction towards the center but the overall system figure is still mimics mild over-corrected. Overall though, at the 7" aperture, I image the scope should give rather sharp images at high power when properly collimated and thermally stable.
It's too bad it falls down at full aperture.