Windows 2003 server SP1 questions

If anyone has any knowledge of this let me know. I've added the service pack to several of my networks servers with no ill effects. I have our main applications server and our Exchange 2003 server. Does anyone know of any issues I might have patching these machines. I'm most concerned about Exchange which is running Exchange 2003 w/ sp1 and on a Server 2003 Os.

Our apps server is Running Goldmine, Mas 90 ( our accouitning software ) and our custom billing software. Most of the work is done off of drive mappings from this machine.

Am I safe doing this upgrade?