I’m using the Cube Mix plus with BT keyboard and mouse (Logitech K810 / Swiftpoint GT) and there are absolutely zero problems with Wifi. Wifi also is blazingly fast on this device and has good range compared to the cheap Atom Z8x00 devices, even slightly better than on my iPad Pro.
Also no problems on the Cube with Wifi, Bluetooth and USB3 at the same time (there are some Intel devices, e.g. Mac mini that tend to have problems with bluetooth when USB3 is used).
The display is good overall, but maximum brightness could be a bit higher for my taste (here, the iPad Pro definitely is much better); also it’s very glossy, so working in direct sunlight is not very good.