Pointed Discussion

Sub-Middling. I wouldn't use it, but some would.

Run with Serra Avatar, in case someone uses a really famous card that I can't think of right now and causes it to deal damage equial to it's power to it's controller.

Not so bad in a Rubinia EDH.

Why is this rated so low when Diamond Valley is rated so high? I'm confused. It's not like a lot of people play land destruction or anything, so it's rarely going to be a 2 for 1. What gives?

You don't have to pay 3 mana to use Diamond Valley's effect.

@Dark_Raider
Because playing this is almost like playing Stone Rain on yourself and then dropping a Diamond Valley. And that's without thinking of the possibility of the opponent having enchantment or land removal. Usually diamond valley or high market are just better. If you need the life and you need the land to produce mana when you don't need to sac, miren, the moaning well also has this effect. There is no shortage in this department that would make you turn to this card, unless you are playing a singleton format.

Would work pretty well with Tree of Redemption

High Market is used if you ONLY need a sac outlet, so it isn't necessarily better. At the time of this posting Animal Boneyard is cheaper than Diamond Valley by $99.75, so if you have it... then good for you. Still, I run this with Miren, the Moaning Well in my EDH deck for my infinite life gain mechanic:

Daru Spiritualist + Shaman en-Kor plus all the creatures with similar effects.

Though to be fair Condemn also works and is much more useful.

While gaining life is a very white mechanic, this should have given you life when they die instead, or something.
Slaughtering your own creatures and drinking their blood isn't a very white thing to do (/understatement); It's black, rather.

It's rated low because:

A) It's an aura. Which means you go down a card when you play this unless you're an enchantress deck; that's one less card in your hand that could have been something. . . else. This card isn't powerful to justify giving a card slot in constructed unless for some reason you really need to sacrifice creatures and for some reason conventional sac outlets like Claws of Gix just aren't cutting it for you.

B) High Market is only $5 USD to avoid the conundrums above and still have a decent land. Miren, the Moaning Well costs even less.

@DacenOctavio: Might be a matter of wanting the sacrifice outlet to do more than just sacrifice+a scant 1 life (is it just that the Claws and Market can be deployed cheaply?). Mostly a matter of getting all one can get in the process. Although that said, I think I'd prefer something like Fanatical Devotion or Martyr's Cause in this scenario, compared to the Boneyard (think persist, EtB, and things like Deathrender all put together). As to Miren and High Market, maybe they don't want any colorless-only lands, for some reason. At least, that's the best explanation I can think of.