Although the interface still leaves a little to be desired, I think Caldera's interface is far more intuitive than Onyx.
Color management and ICC profiling is about on par with what I'm used to (I formerly used ProfileMaker and i1Profiler; Caldera is now using the i1Prism engine as of v9, which is what X-rite uses in i1Profiler.).
Driver availability, ease of configuration, and installing profiles are all ridiculously simple.
I actually prefer using Caldera on a Linux box since the interface is more consistent and you get more flexibility with hardware, but if you're in an all-Mac shop that route works fine as well.