This has been a trend since the early days of the new . The FirePros just don’t benchmark anywhere near Apple’s claims. The odd part is that the D700 is usually outperformed by the D500. That makes me the test a little suspect to me, honestly, but the real world performance has been… well, it’s a beast (but the lack of crossfire or CUDA and poor support of OpenCL temper that a bit). I got one of the first ones to roll off the assembly line and have been using it over a year as my primary machine.
That being said, I run a business that does a lot of native iOS & Mac in addition to game development and I prefer my main machine be a Mac. If I were buying a dedicated machine primarily for UE4 game dev, I’d custom-build a gaming PC from parts. The is just not a good value proposition for that use case unless you place a really high value on using a Mac. If you already have a , though, it’s a great machine for UE4 work, both under Mac OS as well as bootcamped into Windows.