Personally, model based testing completely does my head in!
I like to think that I am not the dumbest person out there, but even after sitting down with HWTSAM, rolling up my sleeves and trying to get into it, I simply couldn't get it to work for the web based application I was testing at the time I tried.
That said, I don't think that means that it can't work, I think that means that effective Model based testing has a steep learning curve before you can get any results and real world benefits over and above other techniques.
I also think that in "real world" testing where time is tight and people don't have that much time to spend learning model based testing (using Spec Explorer in Visual Studio), at the moment is simply too much time invested for not enough results.
Something like Specflow and writing tests myself without the model gives me much more bang for my buck when it comes to pounding out quick test cases.