With cases like the Lifeproof iPad case coming along, the durability question may be addressed adequately. I do find the characterization of AC's being knuckle-draggers amusing, I'm sure I will form my own opinions in the months ahead.
I've been using the 1st generation iPad (which is bigger and bulkier, and by odd luck, more durable) with MovieSlate. I strap mine into a generic iPad case with a flap, and with generous application of velcro, stuck the little bugger to a polycarb "capital D dumb" slate. The real sticks give a good audio clap for the wretched sync to non TC cameras like the 5D, and the app can "sync" (with about a 1-2 frame lag) from the mic on the iPad (assuming the film set is quiet enough) or the accelerometer (i.e. the jerk from the sticks clapping) or both.
But then I'm squarely in the "DSLR quasi-pro" film sound experience right now, which many of you consider not to be professional at all. I'm using what I have as best I can, and I get good results (though I do have a rooftop film shoot war story to share another time).
I'd much rather have a TC-enabled recorder jammed to a TC buddy with a TX on the camera and the iPad app playing as something of an insert slate. Wrapped in one of those Lifeproof cases, I'd be okay putting it in the hands of a knuckle-dragger.