Screen Rants reviewed Strike Back Origins – and gets it. This review, as with the others, doesn’t address the acting at all.
It’s difficult to call one superior to the other, as each series has its own plusses and minuses that become more readily apparent when compared to what came before (which has a different meaning depending on which side of the Atlantic you live on). Origins is probably the more reflective and earnest of the two series, while Cinemax’s Strike Back takes a lighter, more energetically rambunctious approach to the material. In the words of Eric Stoltz’ Lance from Pulp Fiction, it’s “different, but equally good.”