I've mined mainly on Eligius from the beginning of my mining adventure I can say that I have never once had cause to question the integrity or the security of my payouts. I am a small fish and the pond is getting bigger and deeper by the minute but I KNOW I will be paid when I reach my threshold. (and we solve a block) I like the fact I don't have to worry about someone disappearing with the loot and the fact that there are no mandatory fees charged.... although I have set up a voluntary 1% donation anyway.

If you want to leave the best pool around then go for it... but there really is nothing random about the payout structure here. You get paid in a very specific order based upon blocks being solved of course, but you do get paid for the shares you submit that are accepted. If you are impatient and greedy and set your threshold low you may have to wait a bit for some who have not been paid as recently as you to get paid their due share first. If you set your threshold to an appropriate level to match your hashing power so that you hit it at about a 3 day period you wont have to wait much or often.

Just my 2 cents worth but personally I am glad that the payouts focus on those who have gone longer without first... otherwise I might never get paid for my paltry efforts if the big fish got first dibs all the time.