I use organic Similac with my son its a milk based formula. However, if you look on the back were the ingredients are...there is milk and soy ingredients (soy oil). He started with Similac Advanced, the organic kind is the same as the Advanced. Earths Best sells a good formula I hear as well.
I was doing some research today about the organic formulas and found that Similac brand uses sucrose as a sweetner while Earths Best and Parent's Choice ("walmart") uses organic lactose. I am def looking into switching over to one of the other brands. Although all of the articles said that there was no real danger or negative effect of the sucrose it runs the risk of giving babies a sweet tooth. And also, I wouldn't give my baby a lollipop so why this formula. Just thought I would let you know :)