Well I played a little yesterday, and It's fairly fun. Nothing outstanding, but those who like Warcraft setting (like I do) will feel pretty comfortable. Of course I just saw the basic cards so I have no idea what kind of variety and card interaction are offered.
There are many similar games, Shadow Era in particular is not bad it just does not have blizzard behind itself =)
For those who have not seen the game:
- there are no resource cards. You get 1 max mana on the first turn and mana max increases 1 point every turn thereafter up to 10 max. All used up mana replenishes at the start of your turn.
- when to card attack each other they both do the damage. Often it leads to both cards die
- when you attack with your cards you can attack other cards or go directly after the hero.
- each hero has an "intrinsic" an ability that costs mana and allow to do something without using a card
- we see most things that we are used to in a game like this: summoning sickness, a range of abilities such as protector, disable, blitz, etc...
- and of course all of the above is getting altered by specific cards.
I can't comment on card acquisition system yet, as I have not worked it out. You get some card for your wins, and you can purchase boosters for real money in the store.
So far it's looks ok. I'll be playing a little bit more of it.
Some more info about game mechanics:
http://us.battle.net/hearthstone/en/forum/topic/8414831807#1