I agree but Vbgallery has
that allows users to post to Facebook, Filmstrip on Vbulletin home, Random images on forum and so on. None of these are features in PP Pro (not without building plugins)
Vbgallery also integrates better into Vbulletin when it comes down to templates.
One huge advantage for me is when a new user group is created. In pp pro I have to edit hundreds of cats and subcats because the user control is made that way. I know that I can copy a cat but you'll understand why that wouldn't work if you saw the complex users rights per cat or subcat. In Vbgallery this is controlled by vbulletin and therefore incredibly straight forward.
I agree that PP pro is feature rich, but it lacks some of the features from Vbgallery.... I suspect this is because PP Pro is more versatile and cross forum and board compatible.
And these are just a few reasons why I would prefer to use Vbgallery rather than PP Pro.