All I can say conclusively is that installing SP2 was the worst thing I've ever done shy of having my arm twisted into running Windows XP at all. :disgust:
Post install, the startup times were horrible (but I figured I could live with it). Took me forever to figure out how to get rid of the "Are you nuts, you're not using our firewall?!?" icon in the systray (I have a hardware firewall that I'm quite happy with and has never let me down), but finally found that setting and removed the warning.
Then I started trying to use IE and all my problems really started. Heck, I use IE simply because there are a couple sites I visit regularly that require IE (for reasons I don't fully understand) so I do it, quite simply, to make my life easier. I start getting 1/3 or so of the pages I try to load as 'Page cannot be displayed' errors, and nearly any page that contains many different graphical objects won't completely load and of course, look like 'Blood runs red on the highway' with all the little red 'X's.
After searching every support site I could, I only came up with the explanation that some folks are simply experiencing this and nothing involving disabling/changing the new popup blocker, the new firewall, the internet zone security settings or anything else will make it go away if you're one of these lucky individuals.
It was also interfering with the BOINC client (which I use for SETI and Climate Prediction) communicating as I kept getting a never before seen error.
I expected to find that SP2 interfered with some of my non-microsoft software, but I never imagined in my wildest nightmares that it would cripple their own browser.
Thankfully the uninstall worked fine and all the problems went away right along with the service pack.
In short answer to the question... I only installed it because I was tired of 'Automatic Update' bugging me about it. Now I'm willing to look at that damn window/globe thingy for years rather than try it again (at least until I hear that the above problems have been taken care of).