The last supported version of Mac OS X is 10.7.x with MN Client v5.5.5 (Mac only — the PC version 5.5.4 still works on Win7-64bit) — because 10.7.x is the last OS X version to support 32-bit extensions. You think! With the respective hack I already described for (now deprecated) versions of the ISIS client with OS X 10.9, you can take the equivalent steps to connect your Unity on OS X 10.8.x (haven’t tested with 10.9+, maybe this works, maybe it doesn’t), just pay attention that the Unity kexts and other files have slightly different names.
And another freebie.. even though Avid recommends using ATTO FC cards, this works with the original Mac FC cards (by LSI) too. The only drawback is the “limitation” to a 2Gb/s throughput, but that’s sufficient for most HD projects.