First things first.
I have not done a comprehensive review of all the screenwriting widgets available on net. In fact, I have not tried any screenplay widget which is not free. What I believe is that if you can’t find a free widget for doing something, probably that function is not either relevant or important. I don’t want to buy things that I don’t really need.
But if it is any consolation (to myself included), all the screenwriting widgets I have not tried mostly have very poor rating. So the untested ones are screenwriter, celtx, fade in (paid version).
And my vote is for MyScreenplays free version.
MyScreenplays has a very different format which needs a little getting used to. It is different from other screenplay programs that we use routinely. It treats every segment of dialogue or action as a different unit. You have to open these separate units individually and edit. But after some use, you get used to the structure.
Its biggest strength is import and export. MyScreenplays is one of those few android screenwriting programs that get this one right.
It can import and export to celtx and final draft. Export function has been smooth. But my experience with importing has not been that good.
The only difference between free and paid version is absence of ads. I am seriously thinking of buying the paid version for honoring their decision not to restrict certain functions in the free version.
Fade In free which is very good in other aspects lost out here. I couldn’t export my work in any meaningful way. It is possible that this problem with Fade In Free is very tablet specific (I have a samsung 750 (10.1)) and it would work well in other tablets.
The weakness of MyScreenplays is definitely its unconventional structure and interface. But I assure you, it will grow on you. It needs some getting used to.
I should also mention dubscript here which is a final draft reader. It is a useful widget to read all those finished final draft scripts.
As I have mentioned earlier, I bought a tablet for productive rather than recreational purposes. Writing screenplay on a tablet is not going to be as smooth as in a desktop, but you can do almost as good as a job once you get used to the keyboard on a tablet. Having a bigger tablet definitely helps for smoother typing.
I thought I would be doing more outlining than actual script writing on tablet. But I was wrong. I found it difficult to outline on tablet. Outlining is the heavy lifting part of the writing and I found the tablet and the interface too distracting. Nothing beats pen and paper for jotting down random incoherent ideas while you are trying to solve a specific problem.