I'm using it. I did some tests so I could see if file transfer times were increased in any way.
To do this I copied a video clip from one part of my drive back and forth three times, (for a total of 6 transfers). On xp sp2 it averaged 6 minutes and 28.3 seconds
On xp sp3 rc I did the same file transfer on the same drive back and forth three times, (for a total of 6 transferS). On xp sp3 rc it averaged 5 minutes and 43.7 seconds. This seems like a considerable increase, so I will attribute this to the new service pack instead of natural computer variance.
I then tried transferring a different file over my home network. Simply b/c I didn't want to wait that long for the file to transfer. This time it was a shorter video clip.
I transferred only 2x back and forth this time before upgrading to sp3. The file transfer time averaged at 4 minutes and 22.6 seconds.
On sp3 rc it averaged 4 minutes and 2.2 seconds.
In my opinion their are significant performance increases in file transfer times. I did not run any benchmarks; and are my experiences using a stop watch and transferring the files. I believe this increase in performance will be appreciated more in transferring large files such as in an office environment.
EDIT: To get the xp sp3 that micrsoft has released to beta users, you can use this hack http://dailyapps.net/2007/11/hack-at...indows-update/
. It worked for me. The tests I did were done with the RC. I now have the xp sp3 beta. I'm not sure how it differs from the RC but that is now what I have installed.