I'm a Mac user, and I recently decided to upgrade to the new operating system, OS X Leopard. I thought it would be relatively simple to upgrade. But it wasn't. I've spent the last two days stuck in front of my computer working out all the kinks. So I thought I'd post a warning to help any other people in a similar situation avoid the mistakes I made.
My big mistake was apparently my choice to simply upgrade the existing system. It took an hour or two to complete the installation process, but then, instead of seeing an improvement, the performance of my computer slowed to a crawl. It was like swimming through molasses. I kept getting an endlessly spinning beach ball whenever I tried to do anything. A few times the finder froze. I have a relatively new computer -- an intel mac mini -- so the hardware should have been able to handle the upgrade. I was thinking, "Wow, this new system sucks!"
After some slow searching on the internet, I discovered that other people had been reporting the same problem. The solution was that instead of simply upgrading the system, you had to do a clean install. This meant wiping out everything and starting new. So that's what I decided to do. The problem was, this meant backing everything up first -- something I should have been doing on a regular basis anyway, but hadn't been.
So I spent an entire day backing stuff up, doing a clean install of the system, and then reinstalling everything.
Long story short, I'm back in business, and the new operating system works really well. But it took me two solid days of messing with this to get it to work.
Obviously the experience of others may vary. But I'd definitely recommend doing a clean install right away, and not even thinking about choosing the "upgrade" option. But now that the system is working correctly, I do like it.