The Hadraw Shield is a racket so good at defense that Butterfly decided to call it the shield. There are many reasons the Hadraw Shield is so suited to defense; it has 5 plies and it is very lightweight are some of the main ones. This means you will be able to easily maneuver the blade wherever needed and will be able to block even hard to block shots.
JTTAA stands for "Japanese Table Tennis Association Approved". Blades that are used in local and national tournaments in Japan must all be registered in the Japan Table Tennis Association. In the association they actually have crew to select blades in order to ensure the quality of the baldes, both imported or locally-made, are premium. Unqualified blades are not allowed to registered. So JTTAA is indeed a sign of quality, Japanese are so conscious in their effort of quality control.