I'm with HF - my limited experience of NVG shows that, under certain circumstances, NVG can allow you to see cloud B4 you enter it. As a day/night VFR EMS pilot I have gone inadvertant IMC a couple of times - I would like to have seen these cloud banks and had some chance of avoiding entering them.
BTW I remain a huge fan of multi-engine ifr helos.
gags e86