When I started working on robbies I couldn't believe they were helicopters.

They required far less maintenance then any of our fixed wing rentals and
routine 100 hr inspections took less time than a C-172

I recently did experience a down side. A student and instructor oversped the
engine / rotor during hovering practice.

The blades and hub had to go back to the factory for checking and we had to
pull the engine for an overspeed inspection as well.

This will prove costly.
Tom