I ordered a yiynova 20" and have been playing with it a little for the last week.
https://www.amazon.com/gp/product/B01N23PCUZ/ref=s9_dcacsd_dcoop_bw_c_x_3_w
I'm using the software Clip Art Pro, trying photoshop and will try another couple titles as well.
The build quality of the Yiynova is OK and the documentation is minimal.
The cables that come with the Yiynova to hook up to the iMac do not fit very tight in either the Yiynova or the iMac. This has led to a problem with the Yiynova losing the connection to the iMac. I have tried the cables with other computers and it is the same issue so the the problem is not the computer but the cables.
Panda City, the USA distributor has excellent tech support. In the middle of a Saturday afternoon I posted a question on their facebook page and received not only a reply in 2 or 3 minutes but also spent half an hour troubleshooting. Very, very good support. They offered to overnight a new cable at their expense.
The only problem I have with the Yiynova is the hassle of connecting/disconnecting the cables. I don't have room to keep it on the desk connected all the time since I need to use my computers for other purposes. Combine that with the usable screen real estate when using Clip Art Pro and the available room is about equal to what you would have available on an iPad pro. The iPad pro has no setup space or cabling.
Now, I need to decide if I return the Yiynova and buy an iPad pro.