I like both Magic The Gathering and World of Warcraft, and Hearthstone takes most of the stuff I like from both and take out the negative.

Some Magic fans may frown the simplicity of the rules but personally I tihnk it made it perfect for online play, specially the part where the enemy can't do stuff on your turn. It simply make the matches go faster because there is no need to confirm if the enemy wants to counter every single spell and ability you use.

On the WoW side, there are orcs, humans and murlocs. If you like WoW lore, you will enjoy Hearthstone.

Just don't play rogues. They suck. I'm sure the devs were ganked in Southshore when they were leveling and just can't let it go.