With 4 wheel disc brakes I'd say a booster would make them work easier.
We had a GMC pickup in the mid 1970's that had disc brakes on the front only with no booster. They are just harder when pushing the brake pedal. I'd assume 4 wheel non boosted disc brakes would be different from boosted 4 wheel disc brakes, the same as non boosted 4 wheel drum are from boosted 4 wheel drum brakes.
John
