I compared the cheap ones with some $89 Voo-doos, the difference is enormous in favor of these. It was important to give them a long Burn-in period to obtain better results.
Finally, I changed my 15A cables to Transparent XL 20A IEC-19.

Hey, It takes 10 min to change out the IEC. If you feel you are degrading the resale value then just buy the Amazon adapter. It goes on very secure. 

I have a power conditioner that only accepts 20a plug on the iec end.  I would like to try some of my 15a cables but don't want to pay to get them changed and don't like the sound. I have one that would cost $150 to re-terminate.  This power conditioner is the only piece of equipment that requires  20a iec.

I am looking at their 15a to 20a adapter.

I have both adapters from Voodoo. Not sure if my mind playing tricks on me but the lesser $89 did perform less than the $200 one.
Note 1: I only left the $89 in system for few days and couldn’t bare it so it’s has never returned to my system. I seem to be more happy with the more expensive $200 one. Both have life time warranty. The $200 one I bought from eBay certainly went bad on me. I called Voodoo in hope they could repair- they sent out a new one the next day all free of charge. 

Note 2: same power cord, I later swapped out with new 20A plug and I thought music flows even better.

@nasaman 

Both have life time warranty.

I was thinking why would an adapter even need a warranty?  And then you needed it.