I've had the Brydge keyboard for my 12.9 since early November. It replaced a Zagg that the hinges kept breaking on. Zagg was good about replacing the keyboard for free, but after 6 replacements I gave up and bought a Brydge.
It has several minor annoyances, but the swipe to Control Center was "fixed" by using the Assitive Touch in Accessability, Settings>General>Accessability>Assitive Touch. Now i get to Control Center with just two touches on the screen. Perhaps not as quick as a swipe, but it works every time, as opposed to multiple attempts to swip.
The other minor annoyances are for me, backlight for key not light enough, not as easy to open as other keyboards/notebooks I've had (needs a cut out like the MacBook Pro's), hinge slipping when extended past about 130°, and sharp almost unfinished edge around keyboard. It's not sharp enough to cut, but it can be uncomfortable.
The keyboard/keys took a week or so to really adjust to, but overall the typing experience is positive. The hinge slipping is very minor because I rarely have a need to extend the screen that far. The hinges grip the iPad Pro very securely and I've never had an issue with the screen moving up or out of the hinge. The hinge does not damage the screen like the Logitech.
The Brydge 12.9 Keyboard case is the best out of the three I've used and would recommend it highly now that the price has dropped to $149 USD or lower depending on retailer and sales.