We did Biergarten when my kids were that age. It is still one of my best all-time memories of WDW. They loved the Polka band, and danced almost the whole set. Me and my wife just sat there and watched them moving around with such joy. Honestly, I don't remember much about the food, but the whole experience was wonderful. We are going back in August, and my kids are now 8 and 10. It was most certainly one of those moments that can't be re-lived, so I'm not expecting the same feeling, but I am excited to go there again.