too broad a question by OP. there are tons of melee builds in both characters. Both are lots of fun.. barbs usually can tank better due to 2x if not 3x life more life (if cta isn't used on pally) and paladins have more versatility and the best shields in the game.
barbs have way better wpn options whether 2H or dual or 1H +shield. Paladins are most effective with 1H wpn and shield.