I am going to play double devil's advocate when it comes to the hackintosh scene and what is possible and what is not, as of yet...and I have been part of the hackintosh community for quite some time. My current rig is a i7 4770K Quad core, with a Gigabyte MB, and Geforce 1080ti. I have been researching quite a bit and the plain fact is that no one that I have seen has made a hackintosh with the same specs/hardware of what is going into the new Mac Pro; and for obvious reasons, buying the same hardware is just as costly.
Gigabyte socket 3467 MB (C621 AORUS XTREME) which does not even have 10gb Ethernet is $2065 on newegg
Intel Xeon W 16-core (Intel® Xeon® W-3245, same one in the MacPro) has a street price of $2000 according to Tom's hardware.
So without anything else (RAM, Case, Power Supply, HD) we are around $4000. Mac Pro base, just upgrading to the 16-core brings the cost to $8000. So lets say you can get the additional components including a PCI card with 10gb Ethernet comes in around another $1000. So we are talking around a $3k difference in price for a system that will have no support and could break just by looking at it wrong (I have toasted my Hackintosh several times doing updates; but right now I am stuck at High Sierra due to no nVidia support past High Sierra).
The top tier hackintosh systems are currently running Core X series CPUs which quite frankly are no where near the overall capability as the Xeon W series. Clocks and core counts might be similar and synthetic benchmarks show equal or similar performance; but there are quite a few differences. For one the Xeon W used in the Mac Pro have 64 PCI 3.0 lanes from the CPU (yes 4.0 would be nice for storage, but that is about it for right now). Also the Xeon W can access a ton more RAM than the Core X; fairly critical for scientific simulations where lots of RAM is needed. AMD CPUs lack AVX-512 instructions, which is a bummer. I do like the current AMD CPUs.
And to further the issue, here are the things you need to deal with on a constant basis with a hackintosh system; and I know because I have one:
iMessage and Facetime, unless you have time to research and understand how Apple does motherboard serial numbers and machine naming, and you are lucking enough to have a EN0 ethernet port active out of the box, you will never get either of these to work; you CAN get it working, but it is a hassle; and you need to be extra diligent to validate said fake MB serial numbers.
Audio; always needs to be modified to work, and it is even more troublesome if you want it to work via HDMI or DP. (I solved it by just getting a pcUSB DI box from Whirlwind; but I have a audio console and audio monitors, so it works out good for me)
Thunderbolt 3; as of right now I do not know anyone who has hot swap working with their hack, not only that the method of it working is basically running the output of the GPU into either the MB or another PCI card, in other words, not really thought out system wide like the Mac Pro. And you need to boot into Windows in order to initially activate the TB3 cards on the Motherboards.
Sleep and correct power modes and power stepping for the CPU; unless you feel like learning about SSDT and DDST files you might as well give up on this working 100% correctly. My hack will not shut down properly after it has been running for a few days. Sleep almost never works on hacks; but not a big deal for me as I generally never have any of my computers actually sleep.
TRIM for SSDs; you can get it working, it is just a hassle.
Besides all of the above, the minute OS X requires the T series chip be present, the hackintosh scene just died, or if Apple moves everything to A series based chips.
Now let's delve even further into the Mac Pro and what it offers; what PC system can you buy that has TB3 so integrated into the system? Let's say you want to get the same level of compute power as the Vega II Duo (and mind you the Mac Pro can have 2 of them, for $10800, super ouch I agree); it is debatable whether the nVidia RTX Quadro cards can beat or match these because the Vega II Duo is only available on the MacPro, but AMD has something else called the Radeon Instict that you can buy for PC systems, I can't even find a price for the MI60 (which is the closest in spec to a single Vega II), but the MI25 is $2300, so let's assume the MI60 is around $5k, so 2 of them is $10k and separate cards, not on 1 card; so you will need twice as many PCI slots at 16x than the MacPro in order to match. Of course the debate will be on the PC side you could add a RTX 2080 ti ($1300, 16GB) and a V100 Tesla ($8000 for 16GB) for compute. The fully loaded VegaII Duo setup has 128GB of video memory though. A top of the line RTX Quadro card will run you around $6000 (48GB RAM, Quadro 8000). $10800 for 4 GPUs at the level of the MI60 seems like a damn bargain. (4 MI60s would be close to $20k.) Very doubtful, but if Apple and nVidia ever kiss and make up, would it not be cool to be able to add some V100s or a RTX card?
I guess my biggest take away gripe from everyone saying they can beat and match the synthetic benchmarks of the Mac Pro with cheaper hardware are not looking at the overall big picture of the system and what it can offer. I have already priced out building a hack with similar expansion capabilities, using as close to the same hardware and the numbers just do not add up; and even more so, neither does the time involved getting it to work.
My workload consists of light to medium 3D, motion graphics, video editing, typical photo stuff and typical office stuff (word, excel, etc etc.) My biggest slowdown is that I am generally dealing with massive pixel dimensions building stuff for LED walls and Blended screens for live shows.
The problem is that for my needs, I needs something that is very good at doing a bit of everything, single threaded and multi-threaded; and I prefer the MacOS eco system over Windows 10. I have Windows 10 on my hack also just for playing games. I have also compared all my software on my hack running under Windows 10 and OS X and there is no clear advantage to Windows. Even compared rendering on the OS X side using CUDA, OpenCL and Metal. CUDA was a bit faster, but it is also more mature and running on a card that is made for it, so DUH!
If all I had to do was render 3D scenes all day long, then of course I would be looking at the AMD Threadripper. Who would not be?
Comparing gaming rigs to the Mac Pro is pointless because it isn't a gaming rig. If you want to compare anything, spec out some HP Z systems -- the price will be the same if not more. If fact no computers from Apple are gaming rigs.
I will agree though that the base level 8-core Mac Pro is not a good bargain. I think Apple should make a Mac Pro Lite version that uses Core X CPUs, just do a 8 core and 10 core. Start the Mac Pro at the 16 core Xeon W, the starting price of the "Lite" could be $2500-$3000 and people would probably not complain as much. The Lite version could have only 1 MPX slot, 1 x16 and the half length x4 for the Apple IO card.
Nothing in stone yet, but there is a very good chance (90%) that I will be getting a 16-core Mac Pro, pretty much keeping it stock, except adding more storage (2TB, since all of them use 2 drives except the 256GB base), and apparently they are RAID 0. I may hold out for the WX5700X GPU option. Later on I expect I will get a Vega II Duo or whatever else is better at the time. I have been waiting a long time for a proper workstation tower from Apple. My last one was a G5, been on a hack for a long time.