I forgot to mention that I had meant with the adjuster it was better in that it's considerably smaller and simple. It requires a lot less of a rube goldberg device so less chances of friction or turbulance in order to reduce the flow not that there was zero loss.
Basically you've got more control over exactly how much head is applied.
The differences between even internal/external with the same wattage pump and how it'll affect the tank and room just reinforces the point of how specific to a setup each piece of gear is. You just need nice accurate specs! You're technically inclined so I'm sure we could talk ad naseum about these things, haha.