Audphile1,
You are correct, some people will definitely prefer the Rhodium plating over the gold plating; and yes it will be system dependent and listener dependent. I am extremely sensitive to differences (notice I didn't say faults) in higher frequencies, which to me can be tiring in longer listening sessions. Either way, both were large improvements over the hospital grade that the electrician installed initially.
I have tested a bunch of receptacles in my system in the last few years, and some didn't work out: Pangea Premier XL, Furutech FPX, PS Audio PowerPort, Oyaide SWO XXX, etc.....but many of these might be improvements for some, and at a more affordable price
Some made really nice improvements, that I would happily recommended: Furutech GTX-D gold and rhodium, Oyaide R1, and Cardas 4181.....all of these are $150 to $250 each, not cheap.
Happy listening all!