Well, I'm the founder of BeeLine Reader[1], and our extension is used for speed reading as well as accessibility (vision impairment, dyslexia, ADHD). I don't think it breaks websites, since we let the user decide how aggressively it should try to run. There are also night mode extensions, as well as site-specific ones (like for wikipedia) that are great.

1: http://www.beelinereader.com