Rotorhead84 & Salusa: Interesting. Well if pilots can feel a worse 'vertical hop' under certain conditions, then most of the parts of the helicopter are likewise feeling this, so it wouldn't be surprising if components failing earlier than on helicopters that are not experiencing such vibrations (to the same extent).
The 206L Noda
-Matic
nodal suspension system is likely still behaving much the same with either OEM or VHA blades as it is probably tuned to damp vibrations most effectively at the normal rotor blade passing frequency (which would be unchanged regardless of blade type and depends only on RRPM and number of blades).
The VHA blades might be introducing vibrations at 'higher harmonics' which Noda-Matic isn't able to damp out.
I found this set of university project slides on helicopter vibration absorption systems which gives a useful introduction to what is out there:
http://ocw.upm.es/pluginfile.php/438...stem%20ARS.pdf
Slide 7 suggests teetering rotors not great when it comes to rotor vibrations, another slide indicates the more blades the better when it comes to reducing vibrations, while slide 12 says it should be possible to design composite blades to achieve the desired bending and torsional rigidity. But I don't think any of that is trivial to get right!