lt interface vs fe-0/0/x

Hello,

I have an M7i in the lab to play with...

While starting creating topologies I saw i have 2 ways of configuring
them. One is via the tunnel pic, while the other is interconnecting all
4x fast ethernet ports via a a switch

With which option I can cover the majority of the jncie scenarios ?
(specially qos, vpls, l2vpn, l3vpn) Is there one better than the other ?

Thank you

-s