As there are no metrics available for the Mac Pro (at least none that I've seen), no comparisons are available. And the Xeon processor is widely used; go take a look at the Dell website, just for example.
"Faster" is often an ambiguous term for computers. A box can be designed and built for specific applications in which it excels, but it may be no damn good for playing Angry Birds.
I'm sure that the Mac Pro will be an ass-kicking computer, but I wouldn't make any bets that it is the fastest out there.