Who cares if demos are limited, if they do something that your main screen 
reader doesn't do.  This way you can get it done.  Just try what's free and 
you will have more options than you do restricting yourself to one product.
I use window-eyes mainly, but when I need to remove people from shared 
folders on drop box, I use system access, because it finds the remove option 
and window-eyes doesn't.
That doesn't make system access better and window-eyes worse, but it does 
that on a place where I need it.