Got Formula...?

We are onto formula #4 today - Good Start. After attempts at Enfamil and several of the Similac types, we are trying Good Start with "Comfort Proteins" in hopes that Ben's little tummy agrees with this one. We have been on the Lactose Free by Similac for a week now, but still can't get his little system to be regular. He will eat whatever we give him (with enthusiasm), but he is still experiencing an upset tummy, which does not make for a happy baby. We are trying everything before going to the super expensive Nutramagin or Alimentum - both "hyper-allergenic" for sensitive tummies. Who would have ever guessed that I would have a picky eater...no comments, please!