I have several of their products, a Sorcer x4, Sorcer x4+, two Power Bar 8's, and an EAU4 (and plan to get some other products in the future, like some Vivids and a C-Tuner), they all help my system. I've modded the Sorcers and Power Bars recently (which I must state helped a lot), but they worked well prior to modding.
Power enhancement really depends on both what sound you are looking for (or visuals in the case of a/v), and how they synergize with your existing equipment. Not every piece of equipment or every tweak plays well with everything else. I've tried hosts of plug-in and passive tweaks to see what plays well with the Sorcer x4+, and ultimately found a handful that help, but some detracted from the Sorcer's strengths/signature. So to the Sorcer itself may or may not synergize with your tastes and equipment. To me the Add-Powr products bring clarity and air, which is different than say what my modded ECA Extreme Isolation transformer brings which is detail and definition, and so other power enhancement products bring their own signatures. I do have to say if you have a home theater setup being enhanced by a Sorcer or Sorcer+ the visuals may increase in brightness and saturation to the point you will have to adjust settings.
If you are looking for clarity and air I think the Add-Power products will be a great fit, and I have to say that the Sorcer x4+ synergizes incredibly well with the Akiko Corelli plugged into it (since it is also a clarifier by signature). The iFi AC Purifier and Puron Power plug-in also synergize very well with the Sorcer x4+ and so I'm sure would with a Power Bar 6 or 8, Wizard+, Sorcer Apprentice, etc.