Final Draft vs Fade In
Final Draft is $199.99 once, with $99.99 paid upgrades. Fade In is $79.95 once, with free updates. Both read and write the same .fdx files. What else differs?
Both prices are one-time desktop licences, checked on the companies' own pages. Final Draft 13 lists at $249.99 and sells at $199.99. Upgrading from an older Final Draft costs $99.99, marked down from $129.99. Final Draft also sells a subscription called Final Draft Suite, at $99.99 a year or $16.99 a month, and the five-day trial on their store belongs to that subscription, not to the desktop purchase. Fade In, published by GCC Productions, lists at $99.95 and sells at $79.95. Its download page shows the current version as 5.0.15, and demos for Windows, Mac and Linux.
The upgrades are the difference that compounds. Final Draft charges $99.99 to move to a new major version, so two of those upgrades cost more than the entire gap between the two first prices. Fade In's purchase page states that updates to Fade In are free.
On file formats, the two are closer than the prices suggest. Final Draft is where the .fdx format comes from, and its marketing says the software is used by 95% of film and TV professionals; that is the company's claim. Fade In's feature page says it opens, edits and saves .fdx documents, and imports Fountain, Scrivener, Celtx, StudioBinder, Word and RTF files, plus older Final Draft .fdr files. If your collaborators work in Final Draft, either app hands them a file they can open.
Trials work differently. Final Draft offers no free trial of the desktop purchase. Fade In gives away a demonstration version that does everything except online realtime collaboration, and it watermarks printed or PDF output. The demo is free and writes real scripts, so you can test it against your own project rather than a marketing page.
Full disclosure: I build Beatstack, a Mac app for the step neither tool sells. It plans a screenplay before drafting: acts, sequences, scenes and beats on a board, with exports to Final Draft .fdx and Fountain, so the pages can be written in either app above. It costs $39.95 once, with a 15-day free trial, no account, and project files on your own disk. I compared the wider field in Final Draft alternatives on the Mac, and the free options in Free screenwriting software: what free actually gets you.
If you already own an older Final Draft, the $99.99 upgrade is the easy call. If you are starting fresh, try the Fade In demo first. It costs nothing, and a week with it will tell you whether the differences above matter to your script.