It's a bit better than that from my reading: that quote's for He-3, which we don't expect to show any supersolidity (it's a fermion) unless the He-3 nuclei star

It's a bit better than that from my reading: that quote's for He-3, which we don't expect to show any supersolidity (it's a fermion) unless the He-3 nuclei start forming pairs (the pair would have integer spin) -- which isn't really expected until even lower temperatures. The key part of this experiment as far as I could tell was that at the same temperatures He-3 showed decreasing flow rate with decreasing temperature, He-4 showed increasing flow rate with decreasing temperature. This is exactly what we'd expect since He-4 nuclei are bosonic, while He-3 nuclei are fermionic. That's pretty good IMO