One of the advantages of l2tp is that it provides a mechanism for encrypting the data being tunneled

L2TP is also faster and easier to configure with most firewalls

Explanation:

L2TP add IPSec for security it has advantages over PPTP in because data is much more secure and not vulnerable to attack. Also, L2TP protect data from being attacked while moving between the sender and receiver. It also encrypts or secure the authentication process, making it more difficult for someone to listen or hijack in the transmission link. As it uses UDP to encapsulate data, L2TP is also faster and easier to configure with most firewalls. If security is more important to your VPN than speed then L2TP is the recommended protocol.