A quick note on deckbuilders before I explain why I love this game:
There are two main types of deckbuilder, the first is where there are 10 decks of cards in the middle of the table which are available for the whole game for anyone to buy, each deck has 10 copies of the same card. This type of deckbuilder allows you to formulate a strategy at the start of the game and execute it.
The other type of deckbuilder is the one that Ascension follows where there is 1 deck of cards and from the top are drawn cards so that 5 face up cards are always available for purchase. Every card that is bought from this deck is worth victory points at the end of the game.
The first type is all about building a streamlined deck which efficiently ables you to buy victory point cards, while the second type is about buy whatever is the best card available from the 5 face up cards on your turn, hopefully you can choose cards which synergise but often that is not the case.
The reason that I explain this distinction is because this is the first Ascension expansion that really gives you the options of persuing a focused strategy which is atypical of this type of deckbuilder. If there are no cards available that follow your strategy, then you can usually buy one that allows you to draw cards or that helps you remove the basic cards from your deck, or that once played stays in front of you as a permenant buff. On top of that, this expansion also introduces a couple of very exciting mechanics. The first allows you to transform a card into a more powerful version should a requirement be met (usually that you have a certian amount of resources during the turn that you have the card in your hand), secondly a 3rd resource type which can be used to use a more powerful ability on the cards in hand, and thirdly treasures which are obtainable when buying various cards which give you the 3rd resource type.
This combination of new mechanics and the ability to make an efficient deck that follows a focused strategy make this my favourite ascension expansion.