Eligius is a small pool with high variance. Nevertheless, I point a lot of my miners there because of one redeeming feature - you get paid mostly in virgin coins. Sometimes the block rewards go to a payout queue first and you end up getting paid with non-virgin coins and I don't like it when that happens.
You also don't need to register to use the pool and therefore can mine anonymously, if that feature is important to you.
If your primary motivation is virgin coins and anonymity, p2pool is your answer. You always get virgin coins when p2pool finds a block. You run your own node and can determine things like minimum transaction fees for transactions you'll accept into blocks you create.
Can someone explain to me whats the purpose of having virgin coins?
Im aware this based on preference, so whats the perks of having coins thats a "virgin".