The immediately apparent difference between linear and switching power supplies is the absence of background noise. Any of the aforementioned Aliexpress units that cost roughly $50 delivered will do that.
Tales of power supply-related sonic improvements above and beyond noise suppression are... another matter, let's say. In any event, it should be obvious to everyone that spending $500 on a teddy prado or sbooster supply for a $200 wiim makes no sense. But spending $50 does, and will result in a noticeable improvement.