You don't say how you want to use the keyboard, how much you can spend, and how comfortable you are with soldering and minor programming/setup. That may make a difference in what you decide.
I have a Hagstrom XT to PS/2 converter that I plug straight into the PS/2 port on my PC. It works great and preserves NKRO. The layout can be changed with Windows registry edits. My thinking was, why use up a USB port (limited in number) and have an empty port nothing else can use?
Anyway, you have several options to choose from, both plug & play and DIY.