My kiddo plays it from time to time, I watched for a little while and it seemed interesting. Reminded of an easier version of Pokemon, though there was times his monster's died, fainted, or whatever.
Though if you search around different forums there is some hardcore people who play this game. Theory crafting and the best teams etcetc.
I was half tempted to play it too, but there are a lot of good games I have yet to play so I doubt I will ever get around to playing Skylanders.