I found most of my campaigns featuring evil characters..I think the people I was playing with felt a bit repressed. I guess what really matters is the group dynamic. Because a large majority of people who play evil characters have the idea to kill others in the group. But I DMed for a group of cultists that were all bound to the same god, and although their differing methods led to bickering (evil cleric, wizard, and druid), and it was one of my best groups ever. You just have to make sure that none of the pcs are completly incompatable and accept the fact that an evil group will stray from your story even more than the normal heros might.