I'm a bit of a stickler for having to click more times than necessary. So, I don't like having to click from Visual to BBCode to Visual (two clicks) to be able to get an accurate live preview, showing me all the @username links I typed. I also didn't like that my smilies weren't parsing. So, I created a solution.
1) If you click the "Quick Preview" button, it will refresh the Visual Editor textarea with an accurate live preview. 2) If you click the "Visual" tab, it will do the same.
I did attempt to make it automatically update when a user paused typing, but it would not retain the current cursor position right now. This is probably fixable once I delve more into the code behind the WYSIWYG.