SP2 whole package will be out on the 25th. MS suggested that you can do an automatic update (to automatically be put in the queue) instead of going to the site since there would be lots of ppl going to the site, lockup and slow download can be expected.
Download latest drivers and BIOS before doing the SP2.
In my company, we have some crash and burns units that has SP2 already and I think its great. Be sure to burn a copy of the 277MB SP2 package. Once you install it, and got some problems, slim chance that system restore would work, so u'll end up running the recovery.
If you decided to uninstall SP2, be sure you have the unit's drivers available since SP2 will remove it. Desktop units we have have a partition for system os and drivers sot that's no problem but with notebooks we have, there isnt any partition so drivers need to be reinstalled.