There's definitely something to be said about the unique Apple features, in this case a fantastic, compact form factor that's quiet enough to put on your desk and just use.
More importantly, people keep comparing the Mac Pro to workstations, but this isn't really the right thing to do at all. Sure, the previous Mac Pros are very workstation-like, but when it comes down to it they have never been the best workstations out there, even when Apple was getting CPUs a little bit ahead of the rest, as they've always lagged behind overall, regardless of the two year wait until this latest redesign.
And that's just it, Apple has recognised that the Mac Pro just wasn't a good fit for workstations, as there are simply better machines out there if all you want is a big box full of high-end components. What Apple has done is create a professional desktop; a compact, quiet and stylish desktop (you know, that you can actually put on a desk), that uses workstation components to provide professional levels of performance for video editing, audio editing, 3d rendering and other creative areas.
Let's face it, anyone who needed the very best performance should have jumped ship ages ago (and probably has). But for those that are happy with just extremely good performance, in a compact, quiet and stylish package, then that's what Apple wants to give them. For those to whom that all sounds irrelevant, then the new Mac Pro was never really for them to begin with as it always cost more for what you got.