Apple just released Mac OS X 10.5.8 and many users have updated without any problems. After cloning my Mac OS X 10.5.7 drive, I updated my old PPC Mini and tested the new version of the system. Although Mac OS X 10.5.8 installed and started up without any problems, I found some serious issues that convinced me to revert back to Mac OS X 10.5.7. You might not have the same issues since system configurations differ, but you might find it useful to know what problems can exist with Mac OS X 10.5.8.
Sometimes it is best to leave a system alone if it is working fine. I have been using Mac OS X 10.5.7 since it was released and it has been stable and I haven't experienced any problems with it. After installing and running 10.5.8, I didn't notice any general speed or operating differences, so it seems that there are no advantages to updating. The updated operating system took up more drive space and it seemed to use more of my Mac's processing power. If Mac OS X 10.5.7 is working well for you, there may not be any benefit in updating the system and there might be some disadvantages in speed or processing power, especially if you are using an older, slower Mac.
My HP Laser printer couldn't print with Mac OS X 10.5.8, yet it prints without problems with the older version of the system. If you decide to update, check all of your external peripherals, especially printers and scanners, to ensure that they work with Mac OS X 10.5.8.
Spotlight insisted on indexing volumes that were on the Spotlight Privacy preferences list. Removing and adding the items to the list again did not help - Spotlight was determined to index all of my drives. This may be a bug with the Mac OS X 10.5.8 update since the problem doesn't exist with Mac OS X 10.5.7. If you have drives, especially large drives, that you don't want indexed, having Spotlight using processing power to index those drives can be reason enough to not update.
Safari 4 is installed with the Mac OS X 10.5.8 update even if you have been using Safari 3 with 10.5.7. In other words, once you update to Mac OS X 10.5.8, you are stuck with Safari 4. Naturally, many people are happy with this situation, but some of us prefer Safari 3 for a variety of reasons.
The problems I encountered with Mac OS X 10.5.8 might not affect you, but before updating, you should make sure you have a working clone of your Mac OS X 10.5.7 system. That way, if like me, you are not happy with the update, you can easily revert back to Mac OS X 10.5.7. To learn more about updating Mac OS X, see my tutorials, Updating Mac OS X and 5 Essential Steps to Take Before Updating Mac OS X.