Blue Screen: Apple's Leopard has it too

Apparently, the BSOD (Blue Screen Of Death) is not a Microsoft's exclusive. Recent reports of users that tried to upgrade to the new version of Mac OS X, Leopard, point out to a very annoying Blue Screen freezing problem on the installation process.

In fact, Apple has acknowledged that there are some problems with the installation of their new operating system. But they point out that the problem may be related to APE (Application Enhancer). So, if you're trying to upgrade to Leopard and you are faced with the BSOD, follow Apple's instructions for booting into single-user mode to remove the offending software.

The fact that this seems to occur only to users that are trying to "update" instead of making a clean install, rises the everlasting doubt: should we upgrade or clean install our operating systems?

There seems to be a general opinion (mine included) that "clean installs" are always safer, mainly because "upgrading" is the installation method which will most likely leave files in the system that are incompatible with the new OS. Hence, unless users have the necessary tech knowledge to know which files will cause incompatibilities with the new OS, it's always better to perform a "clean install".

But still, "upgrading" has a very compelling argument: you get to keep your personal files - no need to retrieve them from boring, lenghtly and difficult backups. Anyway, Leopard will probably be the last "clean install", you'll ever make as the new "Time machine" feature in Leopard seems to be a work of art when it comes to backing up your data. It is simple and easy to use and it works on the background as if it wasn't even there. The simplicity of it all is even more evident when you plug in an external hard drive. And in the end with all your data easily backed up and manageable on a external hard drive, upgrading to a new version of the OS is a piece of cake.

Installation problems aside, it is also a general opinion that Leopard is a great advancement comparing to its previous version, Tiger, but not as mind-blowing as it should. And that leads to the obvious question: is it better to make smaller but constant improvements on the OS (as Apple has done in the last five years with constant updates of Mac OS X) or to make giant leaps that can totally change the view that people have of their OS (as Microsoft did from 98 to XP and now to Vista)?

What's your opinion?