Alcatraz #1 is a decent effort, but no more. It reads like a mix of Harry Potter and Lemony Snicket - a self-consciously sardonic young adult story. Unfortunately, while the writing is clever, it's not clever enough. While Lemony Snicket and his "Series of Unfortunate Events" began to pall about halfway through the series, Sanderson gets there within a few chapters. The ideas are fun, the story hangs together, but the writing just wears on you - for example, the constant reminder that the (purported) young author is NOT A GOOD PERSON. It reminded me a bit of Steven Brust's Viscount of Adrilankha sub-trilogy - the joke got thin well before the book was over.
Sanderson's adult work is much, much better, and equally accessible to children above 10 - I recommend that they head there. For others, I recommend the first few books of Lemony Snicket's Unfortunate Events series to see this trick done better.