On the Enstroms, where are the pitch links from the swash plate to the rotor head? It looks like a simple shaft with no links?
Inside the hollow mast ("shaft")
Like all other design choices, this involves certain tradeoffs. Being inside the mast, they are less vulnerable to wires, birds, etc; OTOH, more difficult to inspect.
AFAIK, this design has been mostly trouble free, with most problems coming from undetected corrosion resulting from storing the helicopter outdoors.