They are unreliable enough that they don't see full play without some sort of way of sacrificing your lands. The only exception is Tithe, because it's an instant and can be easily abused with Fetchlands.How do people feel about white catch up cards?
Loyal Warhound and Knight of the White Orchid are a hair away of being playable of my cube. Warhound needs to be a human and Knight needs to be 1W. As they are right now, they don't do enough to justify being so useless on the play.
Currently, I only run Tithe and Land Tax and the latter has a buch of tools to use it.