hospital grade or commercial grade receptacles ?

Hubbell and FIM are both excellent.

However, it's sonically more beneficial to go with which ever receptacle has been cryogenically treated.

-IMO

The only difference between standard outlets and hospital-grade outlets is how tightly they grip the blades of the plug. High-end outlets, plugs, and power cords have no advantage - none - over standard equipment of the same capacity except that they look better and feel better. The rest is in people's minds. There are no measurable differences. Not a one. Cryogenics means nothing to power lines. Not a thing.

You've already done the right thing by running dedicated 20A lines. It might help (but only a little bit) if you keep the amps and other components on separate circuits, and only due to potential voltage sags. Some people think digital components put garbage on the power circuits, but I've never seen one measurement to prove it.

One exception might be power line filtering, if you have a problem with noise or spikes. Isolation transformers and the like can sometimes make a difference, especially for source components, but most people don't live in areas with a problem. My advice is to get a dealer to loan you the equipment for a day or two. If there's an obvious improvement, buy it. If not, save your money.

Don't waste too much money on powercord-related stuff. Save your money for better speakers, acoustical treatments, amps, and source components (probably in that order). Those are the things that make a difference. Use your head and reason, don't just read advertising and bogus magazine reviews. How could an outlet provide such a superior connection that water boiled 20% faster? That's poppycock. Put on your thinking cap.

I use Wattgate and even my wife heard the difference. So to answer your question high end plugs will improve your audio and video presentation. As for brands like any thing else you may want to experiment and determine for your self

Hope this helps

Almost all hospital grades (with the exception of the 20 amp Hubbell hospital grade sold by Albert Porter and Take Five Audio) have nickel plated contacts, which I would suggest you avoid. In that respect, you are best to stick with a spec grade receptacle. My personal preference, not having heard the non-plated Hubbell above, would be either a Hubbell 5262 or 5362. I have doubts as to whether I would be able to differentiate between those receptacles.

Different receptacles have very different sonic signatures, and cryo will make a significant difference IMO.

Contrary to the respondent a couple posts above, power cords and receptacles do make a difference. If you can, I would chase down on A'gon some of the "Porter Ports" that member Albert Porter was kind enough to make available. I have one and it did make a difference. Reasonably priced too.

Good luck,