Those are just the default names - you don't have to use either, it's only the folders within (particularly the \data and \Runtime folders) that are critical. You can certainly merge the two if you wish.
If you have set up custom categories, Adamr001 has a tutorial on how to update the content database for new paths. I would re-import the metadata if some of it was for items installed to studio3/content. Remember to go to Edit > Preferences > Content Library > Content Directory Manager and remove studio3/content from both DAZ Studio Formats and Poser Formats after you've moved everything over.
Or you can continue to use both, as DS4 can have multiple content folders.
You could just delete the uninstallers if you have the installers backed up somewhere.
acanthis said:It's not really the two content folders that is bugging me, but the seemingly random way in which content is distributed between them, depending upon the vintage of the product's installer.