Thought I'd open a general purpose thread for this, now that it's no longer a rumor. I haven't read much of the available info on it I'll admit, but I'm interested at least in theory. Especially waiting to see if drawing and painting apps will be updated to take advantage of the Apple Pencil. I have tried Wacom's Bluetooth pressure-sensitive stylus and hated it.
Plus, of course, the large screen makes iOS 9's split view even more appealing.
I think it's too soon to know what to make of this, but I will keep an eye on reviews and app updates.
Here is Mac Rumors' description of the iPad Pro.
And CNET's take, with much the same info.
And
this Macworld review will hopefully be updated in the future with actual hands-on details.