I like 9 mm also, and I think his Kahr is a dandy little gun. But I certainly don't see any meaningful difference, alone a "big difference".
To me the difference is in the concealability (including the spare ammo) and the slight - but potentially critical - speed in reloading an empty handgun. Last, the vast majority of revolvers (I believe) are carried in OTB holsters, while the modern slim 9mms can be rather comfortably carried in an IWB holster... Just my .02..
But as to shells/power - yeah, they're about the same..
