In case it helps your peace of mind, I found that the Porter Ports were well worth it. (Of course, I too could not really A/B them either.) They certainly strongly pinch the prongs of the plug to establish a good contact.
I had mine installed when I installed my dedicated circuits. Whether it was the dedicated circuits, or the outlets or a combination of both (probably the later), my sound definitely improved.
Besides, if you are going to line someone's pocket, why not a fellow Audiogon member!? (Besides Albert is a really nice guy and will answer any question you put to him.)
My two cents worth anyway.