We are facing the same type of decision with DS5 except that we are looking at early entry to 1st and not K. IMO,neither K or 1st will be an academic challenge but I think 1st might have more of a social fit for him. Good luck with your decision--it seems you have some control of it. My decision will be decided by our public school district since we have strict age guidelines.
I can also definitely relate to the different school thing: I have 2 in a daycare 10 minutes from my work in one direction and my oldest is in a school 15 minutes from my work in the opposite direction. When I have to drop off or pick up all them it can take me over an hour from start to finish and more with traffic.
