If The Unthinkable Happened, Who Are Your Children Going To?

horrible but very important thing to decide! i think (90%) sure i will want my parents to be my children’s guardians, my fiancee agrees, his parents are a too old and they aren’t good parents, mine are great and not too old. i wouldn’t give them to my sister (she already has 2 and my fiancee doesn’t really agree with her parenting style) and my fiance’s sister would trade them in for a Prada bag!
i was just wondering how many people leave their children to the mothers parents? or to a sibling? what things did you take into consideration?