All the pumps that come with the 240 kits are loud. Noise is subjective, but for sure, the pump on the H100 will be quieter than the 240 kits' pumps. And it will have control to vary the speed of the pumps.
That alone is worth the price of admission.
You'll get 5C better temps with the kits? Without being able to decouple that xspc pump bay though, that thing is loud.