The monk in the game I DM is about to take VoP, and I'm the one who suggested it. The player is new to 3.x (an old 1e player), and hated the inherent reliance on magic items that the rules presumed. She wanted the character from the beginning to eschew material goods, and only begrudgingly bought magic items because she considered it out-of-character but needed by the game system (the game started at Level 5).
So I showed her VoP, and she loved the idea, and is working towards taking that as her next feat (having just taken Sacred Vow). She's already got the roleplaying down, isn't trying to powergame it, and monks don't have alot of the inherent catches of the VoP, since they typically don't activate magic items, don't have as much inherent need for MI's (with Ki Strike) and even if it is a little powerful, she's the party tank (no fighters, just a monk), so she can use all the power she can get.
As a DM, I wouldn't let just anybody take VoP. That person who got +5 Inherent Bonuses to ability scores beforehand would be right out, inherently ineligbile for VoP because they are violating the spirit of it. Instead of donating their wealth to charity, they sunk it into things they couldnt' give away and used their wealth to become more powerful instead of helping others when they had a chance to. Sorry, you failed the roleplaying requirement for VoP. Although, to be nice I would warn them beforehand it wouldn't work, and not be a rat-bastard DM and wait until they are taking the feat and tell them they can't.
I'll also agree that any PC should be able to carry a wooden holy symbol (or other appropirate modest token of faith), it's not on the list but it's hardly game-breaking and it's very thematic and roleplaying appropriate.