IRRC, Competitive Cyclist had been selling that setup for $669 for some time.
Interesting that the price has dropped below $600.
I can only assume that it's because people are really moving away from wired systems. The Pro+ is only $675. Of course, then you also need to buy the head separately...
$600 seems pretty good to get into power, considering it comes w/the basic computer. Seems unlikely that Psimet or other will beat this with a current hub.