I'd say that the installation of the new quad core server went incredibly smoothly. There was limited downtime, and as of yet, no serious bugs that arose.
The only moderately impactful glitch that I'm aware of was the inability of the new Web server to talk to the email server. This meant that stuff like email alerts when someone sent you a message wasn't working.
I'm happy to say that we've resolved this, and that all email alerts should be working again.