My only opinion - well, the only one I'm expressing here - is that you can hear all kinds of things on Genelecs that you don't hear on NS-10s. Subtle reverb tails, for example. If you want to know what people not listening on Genelecs are missing, NS-10s are one of many good references.
More importantly, Jeremy is obviously a pervert, criminal, and charlatan for disagreeing with me about that. How long have you been in the business, Jeremy? Sheesh.