It's much more secure than SP1 is. As long as your computer is prepared after doing ALL of these steps, you should install it. You have to be completely prepared for SP2 which means. Spyware free, Adware free, virus free BEFORE you install SP2, Also go to this link from Microsoft which also has links inside of it that will tell you what to do to prepare, including programs that are known to have problems which you may have to patch BEFORE you install SP2. Also go to your computer manufacturer's web site to see if any programs that came with your computer (non Microsoft programs) that need some sort of a patch BEFORE you install SP2. After all of the above, you should have no problems. Here is the Microsoft link. Hope this helps.
http://support.microsoft.com/ph/6794/en-us/