After playing with these (someone loaned me some to make a deck and 4 other people had their own deck), I have to say there are many problems with these:
* $4 per 8 cards but decks must be 10 cards (unless using an unmodified booster) and even buying 2 packs is unlikely to give you the cards to make a deck (must be 3+ cards of each of 3 types per 10 cards).
* The price is way too high when only the rare cards have artwork.
* These significantly slow down the game as each player will usually draw one at the start of their turn and must decide if/how to use it.
* It gets away from having tactics - suddenly each player gets a random ability that can have a significant impact on play.
