delays must be different with each provider etc..4K. It looks good to me. Compared to HD, the 4K wins. Here is another observation. When I switch from 4K to HD, the HD sound is delayed. The HD repeats what's already said on 4K. I have Dish.
with DirecTV FS1 was about 3 seconds ahead of the 4K feed (106)
Also I just got a 4K fire thing and it had a huge 1 minute delay.