There are flaws with the comparison. The W9000 isn't just a faster chip, it also has features, like ECC support, that the d700 doesn't have. Additionally, with a PC, one has the option of going with NVidia and the Titan, which is something that you are incapable of doing with the mac pro.
They don't want Titans, but that's essentially what they're getting. D700s don't have the features that normally define workstation video cards, like ECC RAM.
Nope, no ECC. Apple has a history of these sorts of shenanigans -- the time capsule, for example, was advertised as having a "server-grade" hard drive when in fact it just had a bog standard consumer drive in it.
