Regarding the comparison to a Mac Pro, it’s unclear what this Z2 Mini’s top processor would be, but it would have to be quad core. You don’t usually compare workstations on single-core speed. So, if what you want is workstation computing–lots of cores, lots of 3D / GPGPU performance–in a small package, then the Mac Pro is really the only such design of the last few years, as far as I know. The mechanism they figured out to use a single heatsink and fan is unique.
I’ve recently built a PC that outperforms a top Mac Pro. It saved a lot of money, but that wasn’t easy as it required that I include multiple, unusually powerful fans for the case and CPU, and the damn thing is just large and atrociously loud. If you do a little bit better job than I did, then you get something like the HP Z840. That is a workstation. The prices on the various configurations are just as outrageous as Apple’s Mac Pro pricing, though. Although you have to keep in mind, newly-made PC workstations are now 2 Xeon versions more current than 2nd gen MP (Xeon v4 vs. v2), which came out in 2013.
