PMC is where papers go that are required to be open access due to funding or chosen to be open access in the life sciences, generally speaking. It's the officia

PMC is where papers go that are required to be open access due to funding or chosen to be open access in the life sciences, generally speaking. It's the official place for these and a legal copy. Sci-hub generally isn't. If you support Sci-hub you might as well save them the bandwidth for serving papers that are genuinely open access. And supporting PMC is good to support the further expansion of actually open access papers and the funding of them. PMC also makes everything uniformly formatted which is often a benefit, though sometimes equations can be worse.