One of the reasons I’d be interested in upgrading is the color options. Overriding CSS for the many, many places that blue is hard coded is tedious. But since you don’t say what the color options are in the pro version, or how they are chosen, I can’t judge if they would be adequate.
Additional header options… What are they?
Additional Layout Options… What are they?
Webmaster Tools… Such as?
Featured Slider options… Can they be a mix of pages and posts or can you only chose one or the other? I suspect one or the other, but using a featured image linked to either would work around the limitation.
Can the pro theme be automatically upgraded or do we need to manually replace the theme folder with a new version?