I would like to rename my current exch organization. I know I will have re-install exchange. What are the pros and cons when changing the org name?

Well, the only way that you can change your Exchange Organization is by removing all your exchange servers from your exchange organization , and then remove the exchange organization from the active directory completely, because Active Directory supports only one Exchange Organization per forest, so you can't have more than one Exchange organization per an Active Directory forest. please let me know if you need more help on this issue. Regards Alaa Al-Ankar