I don't know why some are saying it's not compatible with 3.5.1; I've had no issues. Perhaps you're just not following the documentation? I'd have to look into what you're not doing properly.
But for me, this is perfect. It takes long posts and makes them much shorter, which means less scrolling and boring things like that, which aren't good in today's A.D.D. culture.
I gave this 5 stars; good work by the author(s).