I have the PorterPort and I feel confident in recommending it. It imparts a clean and uncolored sound. Sort of a reference of neutrality IMO and gets along well with a variety of cords. A no-brainer at the price.
If you decide you want something that ads more life, air, and soundstaging presence to the sound, I like the Synergistic Research Teslaplex SE. I wish to disclose that I have all SR cords and cabling in my system as well as a Powercell 10UEF/FEQ, so YMMV.
All of the receptacles need several days to settle in before judging. I run an extension cord to our garage fridge for a week, changing between the two outlets on the receptacle at mid-week. Even then, they need a day or two to settle in once the cord(s) is disturbed.
Best to you narcissus,
Dave