Having the framework included saves a LOT of time for customizing the style yourself. It's easy enough to disable features you don't want for the users, and in some of the styles it's downright easy to enable the feature in the base, and then give the end user the ability to turn that off (
@Steve F, thinking primarily of you guys at PixelExit).
I like UI.X, but Audentio does some weird stuff with the navigation that causes some add-ons to break since they look for their template edits to change in the standard template names. You then have to dig through and find the new templates he has created and then make a custom template mod for it.