To make is absolutely crystal clear... nUI Pro no longer exists.
There are three versions of nUI as follows:
1) nUI Release -- this is the currently approved release version of nUI available for download from WoWI, Curse and WoWUI.
2) nUI Development -- this is the current development line of nUI and contains all of the features I am currently coding and testing and is available for free download only from the nUIaddon.com web site as it is not approved for "release" status due to the transient and often untested nature of the code it contains.
3) nUI PTR Beta -- this is the current development line of nUI compatible with the current public test realm and also available only via the nUIaddon.com web site due to the fact that it is both highly transient and incompatible with the live realms. When the PTR goes live, this line is merged into the nUI Development line.
There no longer is a nUI Lite or nUI Pro version and any questions or references to either in the forums will either be deleted or edited accordingly in order to ensure that I do not run afoul of Blizzard's new Draconinan policies with regard to addon development.
What people don't get is that I am, ultimately, an artist at heart.
My brush has two colors, 1 and 0, and my canvas is made of silicon.