If it ain't broke, don't fix it. My mother installed SP3 without thinking about it (new SP? gotta be good, she said) and immediately she got BSDs left and right when typing. She uses a transcription pedal and types in a word processor. Something with the USB drivers, or who-knows-what, was causing untold BSDs. It was so bad she couldn't even burn a CD-ROM to back up recent files in case she needed to restore it.
Luckily, a System Restore save point was made, I reverted to before SP 3 was installed, and viola, problem no longer there.
So whatever else it might do, it's not perfect.