Ignoring all their answers, and the policies behind them - Just based on how they carry themselves and answer questions, Pence is head and shoulders above Kaine. Pence has that "presidential demeanor" to him (more than Trump) in how he responds, carries himself. Kaine just kind of comes off as a creepy sniveling lacky.
That and something about Kaine's pointy teeth and smile that just give me the heebee-jeebees