The drag is a funny thing Molgrips – various people have measured it and come up with very conflicting answers but more drag exspecially in the lowest / highest gears would seem to be true
I have both an alfine 8 and a rohloff. I don’t feel any extra drag but I am slower on the bikes with them. could be tyres etc as much as the hub
also both of them have loosened up and got less draggy as they have got older – the rohloff in particular is still running in at several years and a good few thousands of miles. also my alfine now runs in ATF with grease on the main bearings not a total grease lube – this has seemingly reduced drag.
If you are worried about drag then a hub gear might not be for you. Epicyclics will always have drag