Linux.com find Beryl impressive, but, predictably, unstable using an ubunyu box as their testsystem.
Read it here
Since Edgy comes with the latest version of X.Org's server, which has OpenGL built-in, I didn't have to make a choice about which way to add OpenGL to X. As a matter of fact, since I am also running the latest Nvidia beta (9625), I didn't need to have GL support in X at all. But if you're not running the proprietary, beta version of the Nvidia driver, you will need to install software to support OpenGL.
DANGER! DANGER! DANGER! This is not production-ready software. There are both bugs and omissions. Use with caution. You have been warned.