I have been beta testing SP2 in my corporate network environment since it's release. Once I configured about 15 ports and applications on the firewall, I have had no problems. Well except when I tried to uninstall it and it BSOD my computer.
The main reason why we have not deployed SP2 on our corporate image is that it breaks SMS. Until the most recent version of SMS was released, once you installed SP2 on a machine, you could no longer control it via SMS.
Remote Console would not establish an incoming connection on the remote PC. Now that SMS is fixed, we may move forward with it. We have had zero problems with application functionality and about 1/3 of our apps were created in house sometime around 1777. They work though, knock on wood.