For me, it's definitely more fun than the "bubble saga" games I've played. The problem I've run into with those is that you occasionally -- more than occasionally, on some levels -- get served a board that can't be solved. By that, I don't mean it's too challenging; I mean that they literally can't be won. If you need to clear away a cluster of yellow bubbles to drop a bomb but you don't get any yellow bubbles in your bubble shooter in the requisite number of turns before the bomb explodes, you're toast. Eventually, the randomizer randomizes in your favor and you can proceed, but that can take a while.
It's possible that if you spring for the various spells and enhancements the game company wants to sell you, those levels would all of a sudden become playable. But nuts to that. If I wanted to spend money to play a video game, I'd go to the arcade.
It's also possible I may reach a point in Words of Wonder where I encounter similar problems. It's certainly true I've not been able to win every WoW level on the first try. But in every case so far, successfully clearing the level after an initial failure has been a matter of adjusting my strategy. That's sometimes been the case in the bubble games as well, but like I said, if you don't get the ammo you need, what good is strategy?