A lot of people know about Beryl due to its show-stopper feature – a 3D-dimensional “Desktop cube” where each edge of it is a separate desktop. You can place the windows on separate edges and rotate the cube to change the current desktop. For those who are not on Linux, I should say that multiple desktops is a common practice in Linux desktop environments, and Beryl’s cube is just a metaphor for to visualise that old concept.

What’s good

• Switching between windows using their scaled live previews (like in OS X) is great.

• It is an eye-candy. True transparency and realistic shadows effects make the windows looking awesome.

• It is very customizable. You can spend hours to explore all options and adjust Beryl settings by your taste.
• A rich set of customizable window decoration themes.
• Zooming the screen is amusing and pays for accessibility.

What’s bad

• Beryl didn’t work out of the box with ATI Radeon graphic card. This howto helped to fix the problem.
• Java applications do not display correctly. See the solution.
• I could not find an option to display taskbar icons only for a current desktop, as I used to do in default KDE mode.
• There is a sort of conflict of Beryl and default KDE desktop switcher (“Pager”). It is better to turn it off when using Beryl.

[Upd: Unfortunately, the bad things list is growing]

• Beryl makes SuperKaramba widgets invisible if SuperKaramba is started first. See a trick with autostarting order.
• Beryl prevents the system to awake from Hibernate or Suspend mode. The solution is to kill Beryl before hibernating and to start it automatically on awakening.

[/Upd]
Resume: Install it if you care about the desktop aesthetics or want to amaze your Windows friends.