I used a Kinesis Advantage for a few years before switching to the Kinesis Freestyle Edge RGB.
My main complaint about the Advantage is that I kept hitting the arrow buttons in the bottom row unintentionally. Partly poor typing form, I'm sure, and of course I could have remapped them.
The other thing is that the Advantage is tall, so it's not great up on a desk, and it's not that comfortable on your lap. I think it's best in a tray, although some trays may not be tall enough for it.
As for the Freestyle, I like the split design, the customizable layout, and the customizable lighting (I have a different color for QWERTY and Dvorak). Add a couple of USB ports, and it would be nearly perfect. The "6" key is on the wrong half, and I might experiment with a layout that isn't staggered typewriter style.
I do tend to fidget with the position of the Freestyle throughout the day. This is another keyboard that might work better in a tray.
I don't know if I'd call this Moonlander "next generation," but it's an intriguing combination of what I like in the Advantage and Freestyle.