I've written the tech review column for the Writers Guild of America going back about 15 years at this point. Last year, I did a review of screenwriting software -- though it wasn't posted on the WGA website, but rather in my column for the Huffington Post. (The Writers Guild didn't want to be seen endorsing on piece of software over another.)
My preference is Movie Magic Screenwriter. To be clear, as I say in the article, both it and Final Draft -- the two Industry leading software -- are wonderful, and a lot is personal choice. But there are specific reasons that I prefer MMS. You can see the full article by clicking
here.
One important point: unless you're working in the film and TV industry and need software that's compatible with others in the office, there's no real need to use something just because it's used in Hollywood. If something works for you, and it's free or cheap, then it's worth using. You can always just save the file as a PDF and send that out to people.
It's also my observation that most people will defend to the death the software they use, claiming it the best and a gift from God. But usually, they haven't used others.