I’m using the Gearbest case. I like the keyboard but it doesn’t work as a laptop very well — the keyboard has weak magnets and slides off too easily, causing the tablet to fall. I tried gluing down a magnetic strip
http://www.amazon.com/gp/product/B001NGE9C0?psc=1&redirect=true&ref_=oh_aui_detailpage_o03_s00
which improves the stickiness of the keyboard, though I would say not enough. I would still like it stickier. It is fine on the tray table of an airplane, but on a lap, not so hot.
I really like the size of the X98+ and the performance (Win 10 only) seems good. Ideally a keyboard case would work like a Surface, thin keyboard and a prop to hold the tablet. I would buy an alternate keyboard case if it was lapable. (I like the 10 inch form factor for travel or I’d just use a Surface.)