What's the difference between a 'split' keyboard like the Logitech Ergo K860 and a fully split board like the Kinesis Advantage360?

Boards like the K860 are one continuous piece with a fixed split angle and a built-in wrist rest, making them easy to drop in with no learning curve. Fully split boards such as the Kinesis Advantage360 separate into two independent halves (or contour the keys into wells) and are usually programmable, offering far more adjustment and ergonomic payoff but a steeper learning curve and a much higher price.