How I view this being a Consultant..I not a coward but I need to make a living and maintain clients..
If I had >500 users and other techs involved I might be tempted for the rename.
I would rather spend 4 solid days creating the initial new domain up, considering even more time, to get everything just right. I would just hate wondering if a problems come up in the future, was the "rename" responsible.
Just hate "over the weekend", must have the NET up on Monday routines. I have done quite a few in 20 years, one of the most stressful situations, as you are totally responsible, one of the few situations where you are totally on the line.
I would rather face a total disk crash..at least the hardware is at fault.
Monday morning never is perfect, the little details will get you. "Over the weekend" routines are a throughly thankless senario..99% of the setup is perfect, but the spears are thrown for the 1%.
What happens on Monday morning if some odd error crops up which was not foreseen or did not happen on the lab setup, and your network is down or partially down for a few days.
How secure is your employement.
Even with a lab setup, can you afford (time wise) to have an exact copy including the Exchange setup, and the wks connection, plus testing. How much time will this require.
Learning to rename a domain is rather a dead end experience, as you are very unlikely to rename a domain again. Likely, you will advocate suicide before a rename, after the experience.
Setting up a new domain gives you the ability to correct error in your present domain; your registry and AD will be much cleaner. As Mikiemov points out you could export the policy settings