The ST50 is one of the best TVs out there, regardless of price. It offers PQ fairly close to a VT50 at a fraction of the price.
Keep in mind that the model Chad is reviewing is the 65" and the ST/GTs that were reviewed were of the 50"/55" models. The larger panels should have slightly better blacks across all models, so expect the 60"+ ST/GT to have similar black levels to what Chad measured for the 65VT50.
All indications so far have shown that the ST, GT and VT have similar black levels. The EU models have already shown this, and so far holds true in NA as well.