ipsec+tunnel vs. 'pure' ipsec

[Kim Zeitler]

Hello

having run a 'pure' ipsec tunnel for some years now I was wondering if 
there are more advantages in using a tunnel like gre(4),gif(4) or 
ehterip(4) over ipsec except being able to set the mtu or pass Layer2 
traffic?

Thanks for your answer

Kim