I remember a few years back when the BoVD came out and I was playing really, really good cleric character. Most of the party had so much trouble with the DM's uber-vile dragon, but I didn't.. (then again my PC was a radiant servant of Pelor...eh, never mind.

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I remember thinking later on, once BoED came out... aargh! I wish I'd had this book before! I think BoED is great if you really want to a morally pure character. But there are many more serious limitations on the behaviour of "Exalted" PCs as opposed to "Vile" characters. In both cases, you really need the co-operation of both the DM and other players, particularly if your character becomes exalted or vile in the course of a campaign, as opposed to beginning that way.
A friend of mine ran into trouble recently playing A VoP favoured soul, when one of the more mercenary good PCs used part of my friends share of the loot (which he'd give away) to buy an item for himself. It really ended in a huge argument, not pretty.
There is a reason they are classified as "mature" material. You really have to approach them in a reasoned and studied manner as a DM or player, not just as "goodies" or "phat feats". My friend, above has very strong beliefs about morality, and wanted to express that through a PC. Perhaps a mistake, but I can understand the urge.
As for a vile counterpart to the "saint", I'm not sure. There are a lot of evil templates available for evil folk to take."Saint" is however, a very strong template for its level adjustment. I would make the point though, that "saint" is very hard to qualify for, and is entirely up to the DM if the character qualifies. Personally, I add additional requirements to it, to make it even harder.
Malum, would you have any ideas for the "anti-saint"? It wouldn't seem IMHO, very hard a path to become so depraved and wicked (as most NPC villains are) to become an "anti-saint". But please, make some suggestions... I'd certainly be willing to try to work something out, keeping in mind the comments above.