I think we're only talking about these because they're at displayed at every powermac branch and they are shiny.
I'm gonna be honest and tell you what I think about these: They are horrible and the M50 sounds better for about less than half the price.
The PRO700s aren't all that horrible. Has anybody actually listened to a pair of these that aren't display units, and out of a decent portable setup even? They're darker-sounding, have less recessed mids, and are overall smoother than the M50.
But the biggest reason why Audio-Technica released a MKII version of the PRO700 is this: The M50 simply reaches far deeper into the bass and higher up the treble, resulting in a more musical and therefore engaging experience. You hear everything. Then there's the build quality issues that have constantly plagued the PRO700. The M50 being priced lower than the PRO700 was the final nail on the coffin.
Unsold PRO700s will probably come back to AT and return to the shelves as the MKII.

P.S. It really is a common business strategy, isn't it? A company takes its under-performing product, recalls, tweaks, renames, remodels, and sells it at a higher price. Sigh.