Lau or Williams, which is the better approach?
Both of them will "work" in the sense that you can be a fairly competent hitter using both approaches. Both will result in success in terms of overall performance at the high school level, taking all things in consideration.
However, which method will result in pushing the player to the next level? I have to say it is the Williams method, as explained by Epstein.
Regarding hitting ability and power, two of the five skills used to measure a player, the Williams method clearly benefits the average player more than Lau's principles.
It comes down to power. A more rotational model will result in greater power, no question about it. Please name me a power hitter besides Frank Thomas that has used Lau-like principles to drive the ball, particularly with a firm front-side?
Bonds - rotational
Aaron - rotational
Jackson - rotational
Pujols - rotational
Griffey Jr. - rotational
Jimmy Wynn - rotational
Kirby Puckett - rotational
Six players of different sizes who could all drive the ball. And this is why the Williams/Epstein method is of most benefit to most players. It builds power and bat speed.
If you want to be primarily a singles hitter I have no problem with Lau. However, to play at the next level, college or pro, using Lau principles you had better have a great deal of speed and a great arm because if you don't have those skills you aren't going to get the looks you want.
Ask a scount if, all other things being equal, they want a kid with a high batting average and poor bat speed or one with great bat speed and a mediocre average.
Singles hitters in the mlb without speed and/or an arm are an extreme rarity. Sean Casey is one but why doesn't he play every day? Remember, Gwynn was fast when he came up.
If, however, you are like 90% of the population and aren't fast, don't have a plus arm and aren't Frank Thomas or even Brett size you had better be able to drive the ball.
It's a hard cold fact but it is true.
All that being said, neither method will work for any hitter (with extremely few exceptions like Vlad G.) if they aren't smart hitters. You have to pay attention to the mental aspects of hitting. Epstein does a great job of addressing this part of hitting. Epstein also does a great job of translating Williams into more common language and presents tools for using a rotational hitting model.