What is best the grammar checking software to check the grammar errors in novels and screenplays?
None of them. There is no commercial grammar checker that I know of which even approaches the ability of a halfway-competent native speaker. If you're thinking that grammar-checking software will help you with your typos and grammar mistakes, think again. This is one thing that still requires human intelligence.
I checked a few tools like Grammarly, spellcheckplus, writing dynamo and white smoke. I felt white smoke is the worst of all.
Grammarly, spellcheckplus and writing dynamo are all very similar in value, but I found Grammarly is better than both spellcheckplus and writing dynamo. Still Grammarly doesn't catch all the issues, it catches at least some of them.
Also I've found you should know at least some level of grammar to use any of these tools.
Anyway Grammarly is better than others. Check it out.
Hey, don't give me that look. There is no better checker on the market for the German language. Trust me.
If you're thinking that grammar-checking software will help you with your typos and grammar mistakes, think again.
This is precisely what grammar-checking software does. None of them are perfect, but I favor Grammarly (as well as a few other people clearly). You have to pay for the premium features, but the subscription is not outrageously expensive (currently $5.83 / month for the first year, $11.66 for the years after).
The best is Grammarly Software for Grammar and Spelling check. This is because they Software is updated with all the latest rules regarding Grammar. Grammarly Software even suggests you to change segments of sentences which can help it read better. It also provides with spelling changes and suggests best words which could change the boring words in a sentence.