I had Rhino gear on my Disco1 but I let them go with the car when I sold it as the Defender came with a full length steel rack which weighs a ton and took 4 people to put it on.
I did find that the alloy Rhino rack did mess with the fuel consumption on the Disco but I cant say whether it was better or worse than any other rack.
For that reason I only put it on when it was needed which made the light weight very appreciated.

