Recs.
Updated
Free to play card battling game that is beautiful, easy to start playing, and offers a ton of replay-ability.
Specs
Pros
Pro Near-perfect balance between going first or second
There's no significant first-turn or second-turn advantage in Hearthstone. The player going second gets an extra card from his deck as well as "The Coin", a card that gives one extra mana crystal for one turn. This subverts the advantage that would be gained otherwise by the player going first.
Cons
Con Additional "Cards" must be paid for if not earned by continuously playing
There is a bit of a grind in earning new cards, so for those that do not want to spend the large amount of time needed to earn quality cards they will need to be purchased, which can get expensive. Blizzard is however slowly introducing rewards and ways to earn card packs more casually. A player can earn 1 standard pack for the first win in Brawl Mode. They will earn a random gold card for hitting rank 20 each month; and they get a random pack for playing arena, even if losing 0-3.