I have published a PDF presentation on Slideshare about what’s new on WordPress 4.1 For the official codex, other features (for developers) you can visit: http://codex.wordpress.org/Version_4.1 I also embeded the YouTube video demonstrating the new WP 4.1 on a video after the presentation is over.
Exploring WordPress 4.1 Beta 1 Development Version
Interesting appearance of new Distraction Free Writing is one of new features seen and explored on WordPress 4.1 beta 1 development version. What else?