Ya but if you track his game record you'll end up seeing that he is lights out for a while, then when he takes on a true starter role he starts falling apart. There is a reason he hasn't stuck as a starter for any team, but all of us can remember watching him be really good for other teams. He can be brilliant for a while, but it tends to be a mirage.
Ride the hot hand, by all means, but Rask is a number 1, Halak is a borderline number 1 (number 1 on a bad team; even split on a decent/good team, back up on a great team).
I like Cassidy's handling right now.