Since it is limited to developers, not many people will have downloaded it. Also, it's full of bugs.
Hope you have good backups!
Who downloaded the new OSX ML 10.8 Dev. Preview?? I downloaded it and its running so smoothly on my iMac 21.5-inch late '09! ;D
I'm currently downloading it. is it possible to install the OS on an external (USB) HDD? If then, are there any possibilities that the new os installation could mess up my current (Lion) installation?
Yes see my above post ! It could mess up your current install. I'm not sure about placing it on external media as I was not given that option.