I do actually like the overall form factor and styling of the K90. I have an unhealthy fixation on what Alibaba sometimes calls "suspension keyboard". The K95 RGB variant is, to me, quite visually pleasing, even though the LEDs can't be centered on Cherry stems and happen to be notoriously unreliable.
I'm mildly disappointed that the left-side macro keys are obviously just a bolt-on. Not a big deal, although I think it would look a bit nicer as a single-piece chassis.
But unfortunately it's Corsair. And the Corsair branding is permanently engraved into the metal. And it requires Corsair software to run properly. Not for me.
I had never heard of Sun Unix keyboards before - but the ones with macros look like ideal layouts! Very mod worthy, gut out those old domes and rusty electronics for some fresh Cherries, maybe some new paint ... such a beast would be perfect.
But, uh, welcome to GH. I feel sorry for your wallet, lol.