While Final Draft has more of a Mac "look and feel," and therefore seems more intuitive, Screenwriter has immensely more options. For example, when you print a PDF in Final Draft, it uses the Mac OS to print the PDF as a snapshot of the script. That's good: it will look like the script you would have printed out. However, Movie Magic Screenwriter goes further. It turns each slugline into a bookmark, and if you like, it turns script notes in Screenwriter into notes in PDF, so that they
don't print out, but they
do appear when you view the script in Acrobat Reader. In other words, Final Draft is taking the easy way out, and Screenwriter is using the full power of the PDF format.
Throughout Screenwriter, you find similar options that don't exist in Final Draft 6. (I don't have FD 7.) You can cheat pagination. You can change one character's name throughout the script. You can watermark.
On the other hand there are some annoying features. To start dialog with a parenthesis (e.g. if you're indicating foreign language dialog) or indeed to put a parenthesis anywhere in dialog, you have to trick the program. You can't lock scene numbers easily in an outline. I don't see how to get AA scenes even in a locked script. I don't see how you can suppress page breaks on screen.
The issue seems to be a glitchy but intuitive program, FD, vs. a robust but idiosyncratic program, Screenwriter.
I'm frustrated. I really wanted to like the new program.