I don't know how much difference there would be in a holster.
Do you mean carrying the gun in a belt holster? As an aside, even with pocket carry, you should be carrying it a holster.
Anyway, with a proper gun belt and holster, even heavy guns can be very easy to carry. A good gun belt will transfer the weight evenly rather than concentrating the weight in one area, like say your pocket.
So yes, carrying with a proper belt and holster really makes a difference.