I realize this is an old post, but scrivener is my favorite program to write screenplays in. Mainly becuase it can keep everything organized in one file, automatic backups to dropbox, almost seamless transitioning from desktop to laptop, split screen for notes, and composition mode. Pairing it with Nocturne gives me that night time dark mode. I've used Celtex, writer duet, and final draft. None of them work as well as this does. It took a lot of getting used to and finding my own method of organization, but it honestly works the best for blazing through drafts. And to format it correctly with Final draft, All ya gotta do is export as fdx file and then open in Final Draft. I've found FD does have a lot more formatting correction detection, so it's very useful to go through this FD filter before printing or submitting. Scrivener is the most underrated program out there.