Milk snob?

Ok, so I never thought babies could be milk snobs, but I think I have one. Since about 2 months old we put kyle on soy formula. We decided to do the ready to feed stuff, since he had a sensitive stomach and It was so easy and quick. We tried to switch him over to powder since it is so much cheaper at around 5 months old, and he started spitting up really bad and just acted a little different. So back to ready to feed. Tried again about a month ago. He would not finish his bottle's, kept pulling them out and just acting different. So, you guessed it back to ready to feed. We tried AGAIN last week, and would not finish his bottle's etc.. So I bought the liquid gold again and he's back to downing his bottle's again. How can a baby really tell. They must taste a little different. Can't wait until he is 1, so we can save a lot of money and buy D milk.