No, it's not a general problem. Any system update might have challenges for an individual user - but, most often, updates install with no problems resulting.
My recommendation is to restart immediately before you apply any system update, then ignore the urge to run other software while the update is installing. It will take some time, but the result is likely a more stable system.
Keep in mind that you will get other updates after you update to 10.5.8, which are not available prior to 10.5.8
So, you would run software update again, after the 10.5.8 update. More updates will appear then.
If you are still concerned - be sure to make a complete update before you do this, which is a Good Thing™ in any event.