One of the dangers of using WPA2-PSK is the possibility that an attacker may setup another wireless network with the same SSID and even use the same access point MAC address via MAC spoofing. The attacker then may use a deauth attack to cause an internal computer in the network to have to reauthenticate, allowing the attacker to recover enough of what he needs to eventually bruteforce his way into your wireless network.
However, I'm not sure if this attack method is mitigated when using something like WPA2-Enterprise. I'm a system administrator and it would be relatively trivial (< 1hr work) for me to setup WPA2-Enterprise with an internal RADIUS authentication server and migrate away from WPA2-PSK. However, does this mitigate the evil twin problem?