The Pro uses costar-style stabilizers made by iOne which are as thin as a paperclip and probably as fragile.
The Trigger uses Cherry-style Stabilizers, the only one that does uses Costar stabilizers is the Quickfire Rapid (which is the cheapest and best keyboard from Cooler Master).
Anyways, your son probably wants a gaming keyboard, backlit would seem nice to him but you still need to worry about quality. I won't lie, he'd probably be happier if he got one of those "fancy" keyboards like Saitek Cyborg or a Razer Blackwidow Ultimate at the start, but you should try to give him something that would be better for him as a keyboard, not something that's better only as a table ornament.
The CM Trigger does indeed seems to be the best choice, as the Logitech G710+ currently seems to have some quality issues regarding the backlight...
And seriously, the Cherry MX Brown version is at about US$ 100 at Amazon.