Both of my sons love the Thunderbirds, and Talking Virgil is a hero in our home. Our four year old unwrapped all of Christmas presents last year in a desperate hurry to find Virgil! He was of course an extremely satisfied child as he can play for hours having adventures with his hero.
Educationaly its all imaginative play, and if you can dress up as a pilot yourself then two of you can have an adventure together, rescuing all and sundry around the home from the most terrifying accidents. Perhaps because he has had so many adventures, he had an accident himself and his head fell off. He was glued back together, but has now got to be more carefull when abseiling down the kitchen walls! Perhaps, because of the adventure hero image, these toys are subjected to more than the average terror that four year olds are capable of, and therefore being a bit more robust could be helpful.
However, having said that, he is a much loved toy almost a year later. You cant do much better than that can you.