Over the internet people have been saying that this is one of the biggest sets in Pokemon for a long time because of the exciting new Pokemon type dragons!
There has not been a new type for years since the addition of dark type and steel type
along time ago. In my opinion there is nothing really interesting about dragon types because there is not a new type of energy (dragon type Pokemon use lots of different energy types for their attacks). Some of the new dragons will be heavily played in the future and those Pokemon are Garchomp and Hydreigon.
The EX Pokemon in this are not really that good and they wont be format breaking like
EX Pokemon like Darkrai and Mewtwo. However we are seeing two new types of special energy called Blend Energy and they represent either Fire , Grass , Psychic and Dark or Steel , Lightning , Water and Fighting but only one type at a time. These energy cards will help dragon type Pokemon because of their multi energy attack costs. In conclusion I don't think this will be a
very good set for competitive TCG (with a few exceptions) but its very interesting to see a new type of Pokemon.