The defensive rebuke makes you a target in melee more often. As a squishy, I appreciate that. The healing is good, average healing what, 13+7? Heal 20 damage every 2nd or 3rd round? Assuming a hit every round, anyway. Either one, really. The rebuke seems more proactive to me...
Well... I already have four swift action abilities (3 attack boosters, and WRT) and three immediate action abilities (all defensive, but only one personal. one is 1xday, though), so I expect that my swift actions are going to be used up all the time for the most part.
I also have Thicket of Blades, Combat Reflexes, and Stand Still. So if you want to get away from an enemy that I threaten, you can just move away and the enemy won't be able to follow you very easily.
And free healing is nice. This is enough that it actually could matter in combat, too. So if you get stabbed and want to get away, you can just move and I'll try to "lock down" the enemy. If you're still within 10 feet on my turn, I might get to heal you also.
So I think I'm going to stick with the healing one.
However... Defensive Rebuke + Stone Power could be... awesome.
God... so hard to decide! I want both!