I hate to be the hipster but I played Clash of Clans before it hit critical mass. I was one of the first few members of the Touch Arcade clan and was really excited for it despite hating freemium games and timers. Eventually my enthusiasm waned and I wished it had more meta games and systems to it.
Toy Rush seems to have that down by infusing card packs into the game. Even simple things like going to upgrade structures feels like a meta game. Instead of simply chasing clash of clans and making a direct copy with a different skin, it makes it more of a game.
My only big gripe currently is that you either need to connect to Facebook or sign up for Uber's own social gaming network instead of using Game Center. This makes playing on multiple devices or going social a chore.