always want to see to how the ball comes off of wood, rather than aluminum. I remember Blake Dewitt (currently 2B for Dodgers) used to take BP after all of his high school games with a wood bat for scouts. He never used it in games, though... for obvious reasons.
The thing with Harper, is that he's so talented, wood/aluminum doesn't make much of a difference for him. He finished high school a year early and went to play JUCO ball to play some better competition. He's coming out of JUCO and going pro this year... and I would almost bet that he approached the JUCO coach prior to playing ball for them, that he'd come if he could swing wood for the year to prepare himself for the MLB. I know I wouldn't have turned him down.
Can't link it at work... but he's got an epic homerun in Tropicana Field in which he hit the roof above the seats in right field. Estimated at 500+ feet... he was 16 at the time (I think).
If you can find the article in the sports illustrated archives, I remember a story of when he was playing on a select team in a tournament in Alabama. He was one or two years under the age-level for that tournament (so he was 10 playing with 12 years olds... or 11 playing with 13 year olds... something like that). He returned home from the tournament and his mom (who didn't travel with him) asked how he did.... Bryce replied with "i did ok". Bryce's coach called home later that week and asked Bryce's mom if she'd heard how Bryce did. His mom simply stated that Bryce said it was fun and the he played ok. Turns out, he went 12 for 12 with 11 homeruns and a double... playing with kids two years older than him.
He's a phenomenal talent... but so was Josh Hamilton. I hope he pans out. If the Nats get him (Boras is his agent, I believe)... they'll have the two most highly sought after draft prospects ever. Strasbourg looks to be the real deal already.