I took my Thomas adoring son to the train show here and they had different gauge trains of Thomas and Friends. He is going to be 5 and has the wooden tracks and the blue battery operated ones and the take-a-longs, but he really wants a "real" train like at the show. My question is which gauge is better suited for him? He really liked the G one but I see more Thomas cars available in O - any advice??

I might be partial, but I would go with O gauge mainly because of availability. O gauge is a very nice gauge to work with and if he has a life long interest, a more collectible value as well....