There is no use case where Right-Hand Circular Polarization is better, or preferred to, Left-Circular Circular Polarization.  When a UHF RFID reader “fires” it’s antennas, it does so in series…1,2,3,4 -1,2,3,4 – 1,2,3,4  etc.  So, if you have only ONE reader in the vicinity, you can mix and match left and right polarity as they never fire at the same time, so no antenna ever interferes with another from the SAME READER, thus no interference. 

 

However, when you have multiple RFID readers in close proximity to one another, it is advisable to use all LHCP on one reader, and all RHCP on another.  This way they don’t interfere with one another.