I don't show, but have used the wing bands and the leg bands. We were not happy with the wing bands. The leg bands were and still are our favorite bands. We did the various colors so that we could site identify the breed with the color leg band and the feather color we saw. We had a few birds that were similar and it made it easy for us to be sure of the breed.
We used wing bands on our first flock and found when we were processing the excess males that the wings were torn t the point there was no meat to eat. I felt horrible after and we looked into other methods to mark them. With using the leg bands and various colors we can have 4 breeds that look similar and not get them mixed up for breeding.
Currently, the flock is young. POL is not until Sept or Oct for the layers and later for the Orpingtons, Marans and Dorkings. It really is all personal preference.