All of them are good bikes and will get the job done, so it comes down to feel. So get the one that he is the most comfortable on, not the one with the best parts or the best deal. Last thing you need is a complaining 12 year old 
Best advice, although even if you do hide the price tags, not many 12 year olds will be considerate enough to say "Oh, wow, I like this bike the best, but it's too expensive so I won't ask."All of them are good bikes and will get the job done, so it comes down to feel. So get the one that he is the most comfortable on, not the one with the best parts or the best deal. Last thing you need is a complaining 12 year old![]()