We visited Storybook Orchard in Story City for the first time today. We were there to pick apples and now having tried them, I'd highly recommend buying apples there. The u-pick process was a bit confusing though.
When you arrive, you call 515-708-0021 and then someone eventually comes to give you apple bags and then guides you to trees which have ripe apples. When you return to pay, you wait again for someone to come. We spent 5 minutes picking apples and 25 minutes waiting.
That being said, the trees were full of ripe apples and it was really easy for my kiddo to pick them, so in that regard it was a great experience compared to other places we've picked apples at.