Impressive industrial engineering
I think buyers (and maybe even Apple) may come to regret some of those design choices, though.
It is clear that this product is in part designed to push Thunderbolt as a storage connection method, given that most Mac Pros will be sold to people who have lots of big files, and you cannot fit any additional internal storage.
It is also clear that second-hand values of these things will drop off a cliff in a couple of years, because while at the moment they're very powerful, GPUs are advancing at a hellish rate (CPUs a bit less so, but still), and whatever the Mac Pro has got, you're stuck with, forever.
My PC is a whole different beast, but is similar in size, shape and role to the old Mac Pro. And like the old Mac Pro, I can fit a lot of storage and compute in it - I've got six free internal drive bays, a slot for another graphics card, the CPU will talk to 32GB of RAM (that's an i5 limitation, apparently) etc etc.
The Mac Pro is an odd product. The iMac makes sense; it eliminates wires, gives you an instant piece of room art, requires nearly no setup or assembly. Its limitations are justifiable given the benefits.
The Pro, on the other hand, only looks good for the few minutes before you introduce a boatload of wires into the equation, and then it looks like an art deco electric ashtray.
And there are some bizarre constraints. Only 64GB of RAM. The graphics cards are workstation models, so won't be noticeably better than a much cheaper regular card for most things. A removable CPU has added complexity to the motherboard, but there's no indication that Apple will support upgrading it. And the Xeons they've selected aren't that quick, either.
And the lulz don't stop there. When you buy a computer for £4,000, Apple will still ding you for another £40 for a keyboard. They don't chuck in £200 of AppleCare, even if you spend ten large. twenty five quid for a half-metre Thunderbolt cable. There's no on-site or next-day service for your computer you just spent a car's worth of money on.
It looks great, and it's incredibly clever, but as a value proposition? I'm not seeing it.