Hello,
I am facing a serious problem choosing what layer of my multilayer PCB is the best to put a groundplane. Can someone advise me?

I often put the groundlayer on top, but yesterday I had a EMC-course, and the people overthere have another insight.
They say it is best to put it on an inner layer. They say, because it must be “unbroken”
Also they say NOT to use power planes, but just to route each trace needed for a power pin.
This is why (according to them): The power plane and the groud plane are exactly the same, for HF signals.
But, they need to be stitched needly together(for HF reasons) But you can’t ( for DC reasons)
So it is better NOT to work with a powerplane.
Now I see the following advantages / disadvantages:
Groundlayer on top:
-Each smd pin for ground directly connected (adv)
-Ground layer broken by placing parts (dis)
-coupling of the return path in x-y direction uses less copper area (dis)
Groundlayer inner:
– Groundlayer more continious (adv)
– Not broken by placing parts (ground layer is running under the parts) (adv)
– every smd pin that needs a grn-level needs a via to connect to it (dis)
– coupling of the return path in z direction uses whole trace area (adv)

What do you think of these arguments? What is, in your experience, the best option?
I use smd parts and a micro running at 72 MHz.