I'd also like to see what others think about Aura Mastery.

I tend to find that I get much more use out of 1 point in improved judgement (for the range extension) than I do out of AM. In most cases; the amount of damage that AM can help prevent is minimal. This may change for heroic encounters but AM's best use is for damage that could one shot the raid. The best usage, and only real usage, of consistent AM use was on heroic LK. Sure it could help for 6 seconds on a fight but how much does it really help when you are getting consistent damage every 10 seconds?

It may be a personal playstyle thing; but I don't really like AM at all.
AM like Hand of Sacrfice is a great cooldown when used at the right time.

An example for you.

Magmaw does around 100k damage with Lava Spew. If you use a paladin with resi aura and aura mastery, that damage is reduced to 75k(ish). Thats quite a big jump when you consider it hits everyone.

I would take Aura Mastery over range extend any day =)