This is my daily driver and I really love it! It's mechanical, split and the layout is really not esoteric. The major upside from the UHK would be total firmware configurability, not an option on the Matias Ergo pro.
I would have to remap 'Mouse' though as this is the place for my 'Ctrl' key (I use Emacs a lot).
I use this keyboard at home. While it checks everything off on my list (split, ergo, mech keys, ten keyless), the build quality feels a little cheap i.e. Loose keys that stick often. For ~$200 I expected more. Looking forward to the uhk.