The OP probably made a decision some time in the eight years since his original post.
Still, for the sake of the current discussion, I have a Sigmas EVO3 combined with a Synchro EVO3. The Puritan PSM 156 made a bigger difference (=improvement) to my system than did the Isotek combo. As always, depending on the quality of the electricity coming into your house, YMMV.
Still, for the sake of the current discussion, I have a Sigmas EVO3 combined with a Synchro EVO3. The Puritan PSM 156 made a bigger difference (=improvement) to my system than did the Isotek combo. As always, depending on the quality of the electricity coming into your house, YMMV.