I can't agree with this.It is 100% in character for any character of any alignment to use any item that gives them an advantage. The only exception I can imagine is if it was an intelligent artifact that was evil, and the character was a Paladin, but even then, there are plenty of IC reasons to use an evil artifact to do good.
OK, so maybe that Evil item you found does give you an edge. Do without it. You'll get by, and you can doubtless find something almost as useful that won't taint your soul.
My primary character is CG. He is an excellent example of "the ends justify the means as long as you serve the greater good". And yet even he has real limits as to what is acceptable in serving the greater good.
My character has a very close friend who has for some time liked to use a certain item. This item is evil. My character's friend used it to do good, and yet my character was ALWAYS troubled by this item, and continually mentioned it to his friend. One day my character's friend dropped the item by mistake and didn't notice. My character promptly picked it up and hid it, later destroyed it, and never said a word about it to his friend.
- Aloro