Hmm...I'm not really a fan of either of these. Neither one is on my list.
John is so plain and
Jacob is so popular! I think between the two I'd have to pick
John because it's a family name and
Jack can be a nn for it which I love! :)

"There is nobleness in the name of
Edmund. It is a name of heroism and renown; of kings, princes, and knights" -
Jane Austen, Mansfield Park