Agreed. They are very unpredictable. Their ON day can be really amazing, but in their OFF day, they can lose to anyone, no matter the rank and quality of their opponent.
I think its what makes the US challengers so compelling. A guy like Kuznetsov can't do a thing outside of the US - and then guys like Williams, Klahn, Kosakowski, and Sandgren can also post great results. The added intrigue with this challenger is that you get the Blake's, Ram's, Levine's, and Ginepri's of the world who are just as unpredictable.