I haven't been during what I think is a very busy time, but we haven't had bad experiences with the lockers. My "trick" is to head back back and further back. No one seems to realize that there are multiple kiosk/stations for the banks of lockers, and they go back (specifically thinking of MIB right now in my head). Everyone clumps at the easily visible kiosks. I just scootch to the back and find no line or a much shorter line.
And I try to not get a kiosk that is in full sunshine...that makes it hard for me to read, and also seems to mess up the touch screen.
OH! Use your knuckles, not your fingerpads, to go through the screens. For some reason it just works a million times better. Learned that from a Team Member when I was having problems!
And don't have a kid set the fingerprint. Their little fingers don't fill the pad and it can be a pain to get back into the lockers. You can get a TM to help, but why waste that time if you don't have to? It's an adult job, to set the fingerprint.