Most of us got into Transformers as toys before the show came out - so if he likes Animated on their own merits as toys then why not get him Animated? Not saying you have to, but don't rule it out either. If he wants RotF, maybe start with a Scout or too and see how he goes before deciding if you wanna buy him a Deluxe or Fast Action Battler.

The problem I find with some kids these days with current Transformers is that they lose patience after transforming it for a while and cbb to keep playing with it.