Split-adjustable, contoured design that maximizes comfort and boosts productivity. Mechanical switches, onboard programmability and more. Available Bluetooth and ZMK open-source firmware.
I guess for me the biggest difference compared to a Charybdis is that it's a professional product.
I love the Charybdis as a project, but due to the price, I would rather go for something that can resist the test of time.
Trying out a Kinesis Advantage was what really got me into ergonomic keyboards. However, I spent very little time with it before getting an Ergodox (Hotdox), that I stuck with for years. That whole time I thought that I didn't like keywells.... but really I just didn't like the (orthorinear) Kinesis keywells. I know this now after building the dactyl manuform that I use every day.
If you can get a sense for what you want I highly recommend getting a dactyl manuform. Nothing from a company is remotely close in terms of customization. If you can/want to build it yourself even better because you can cheaply experiment and find out what you like.