if you look at the last 60 years of history, it is clear that "BNW" is much closer to what is actually unfolding in reality.
This is something I used to be certain of, but recent developments have sort of thrown that into question. The way I used to see it was that while BNW described something which was more likely to become a universal reality, 1984 described something which has at various times partially come into existence in parts of the world, notably in nations which are nominally "communist".
If I were a high-school level literature teacher, or something, I would assign BNW and 1984 as complimentary readings. It really doesn't matter how "original" 1984 is, because it describes the other side of the coin that BNW is one side of. The near future is likely to look like a synthesis of these two fictions. In terms of the credibility of BNW vs 1984, the one thing that seems doubtful about BNW being a better representation of reality is that the dystopia it illustrates is actually dependent on an almost sublimely efficient social-design. There's actually very little bureaucracy involved, as Huxley's imaginary social order is really self-sustaining and automatic. The kind of (retarded/deranged/cowardly/etc) genius that such a feat would really require is actually beyond the powers of our society at the moment, even if we do possess (or will soon) the technology to pull that kind of shit off. For that reason, a lot of the direct, "in your face" police-state totalitarianism described in 1984 is actually more likely, perhaps as a kind of intermediary stage.
Anyway, no valuable comparison between the two books can really be made without also understanding that Orwell designed 1984 to look like the mutated outcome of leftist state control. Despite his own leftism, Orwell was suspicious and critical of state communism. Readers familiar with some of the ideological drama related to events in the Soviet Union will quickly recognize "Big Brother" as a representation of Stalin, while the "Goldstein" red-herring is obviously a stand-in for the real-world red-herring, Trotsky.