IKEv1 vs IKEv2

Summary:

1.IKEv2 does not consume as much bandwidth as IKEv1.
2.IKEv2 supports EAP authentication while IKEv1 doesn’t.
3.IKEv2 supports MOBIKE while IKEv1 doesn’t.
4.IKEv2 has built-in NAT traversal while IKEv1 doesn’t.
5.IKEv2 can detect whether a tunnel is still alive while IKEv1 cannot.

Check this link for more info:
http://www.differencebetween.net/technology/protocols-formats/difference-between-ikev1-and-ikev2/