I have not seen any improvements. It broke one program for me, and made
another act funny. Copying and moving files now run faster, more smoothly.
Before SP-1, if you were listening to music (mp3's) ... your internet
downloading would slow way down. I haven't tested this yet under SP-1.
If you have a second hard-drive/partition, you should learn how to "image"
your Vista partition. That's the easiest way to go-back / recover from
disaster.
good luck,
NetLink