One issue why I don't use it... Rated 2 out of 5 stars
It's nice. But one thing has to be fixed or it is useless for me:
After hiding the sidebar, it's a pain in the ass to let it re-appear. Because when I move with the cursor on the very left, the cursor turns into a resize cursor. So I have to move the mouse 2 pixel to the right to hit the correct click-spot that lets the sidebar pop up again. This is very annoying. It should be plain and easy like this: I move my mouse to the very left of the screen without having to aim, and click. Voila.
If you see the problem in a full screen window, the problem is possibly caused by your platform configuration. For example, if you put the Windows taskbar or a toolbar at the left edge of the desktop with "always on top" option, then it will grab your pointing on the screen edge.