Turbomeca make great, reliable engines and so does PWC
The difference is in the customer service and spares support and PWC have it over Turbomeca.
The PBH deal might take a bit of research to figure out which one is a better deal but i guess thats pretty obvious.
It depends on where youre operating the A/c and where the nearest replacement engine/components are. Ive heard of PBH deals where theres not even a spare engine based in country!
Did not like the Arrius engine in the EC120 and i only hear good things about the PW206 either way the EC135 is a great ship