The rings aren't really 'bad performers', it's more that there's a change in expectations of what you can and can't do. It's all to do with antenna matching, and having an antenna inside a metal ring. It makes it both more secure and slightly difficult to read (hence more secure). Sometimes with the rings you need to try different orientations, like horizontal ring to portrait phone or vertical ring to portrait phone. Just take your time and slowly scan the phone, when you do find a trigger point, even if it makes a read fail sound, try more around there or try a rolling read in both orientations. It's quite different to using a 'standard' tag.