I was wondering what it means by to have flex: high... Does that mean high flex and is that the reason why racquets breaks on a strong smash?
High flex means that the shaft is more flexible. It gives those with a slower/weaker swing more power. However, those with fast swings don't get as much power out from the racket as the racket 'unleashes' its power too early. The flex doesn't, as far as I know, have anything to do with the actual durability of the shaft. Durability depends on the material, how it's made, if it has a defect etc.
Flexibilty on a racket is'nt a bad thing. It depends on the players preference and needs. If the player is'nt a very strong player and seeks more power, a slightly to high flex racket would be good. High flex gives a player more power, but lesser accuracy. It gives more power due to its whip when you swing the racket. However, a high flex racket breaks faster than a stiff racket if you can really hammer the shuttle. Pros on the other hand, uses stiffer rackets, as they are powerful enough to flex the racket to get enough power out of it, and the extra stiffness adds to their accuracy in shots. Take a look at this picture. Lee Chong Wei is using the AT900power which is rated Stiff. Imagine what will happen if Lee Chong Wei is using a high flex racket?