Doug has a short summary of some myths about kids and screens. The one I struggle with is number 3 that screen time is wasted when compared to outside time.
I have the article Doug referenced in my queue to read so we shall see if my mind is changed. I've watched my 4 year old when she gets a screen and turns into a zombie. I've also watched her climb at the park and work out problems playing with other kids.
I find it hard to believe that one type of interaction isn't much more valuable to her development and that activity doesn't involve screens.