I played an epic level paladin and I will swear by DS. =)
It can make the paladin a very effective defender/controller if used with a combination of feats and powers. My current character uses the following:
Feat:
Contagious Challenge : enemies adj to target of divine challenge is divine sanctioned. Good for challenging multiple enemies if they are clustered.
Honored Foe : Gain six temporary hp when a marked target attacks you. Effectively gives you a "resistance" of 6 when attacked by the multiple sanctioned and marked foes.
Powers:
Knight's Defiance : Effect that pulls all enemies within 5 squares of you adjacent to you. Then make an attack on one of them. All of them are "divine sanctioned."
Just Radiance (Justicar Paragon Path I think): Close burst 5 attack, if hits, enemy cannot make an attack that doesn't include until end of next turn.
Basically with some of these powers, the paladin can really defend the party. Of course, unless the creatures wish to suffer the pitiful damage of ignoring the sanction and the -negative attack rolls. Otherwise, the paladin WILL get surrounded and attacked. Hence, being able to take the punishment is a must. However, it is very hard to kill a paladin defender if your team/friends are there.