What makes a good actor? Perhaps, it's losing oneself in a role. Take Tom Cruise, for instance. In every movie, he plays the same character: a cocky know-it-all prick. Sometimes he is a pilot, sometimes he is a lawyer, sometimes he is an agent, but he is always Tom Cruise. This is not acting; this is posing; in real life, he's a cocky know-it-all prick as well.
Not so with Jason Alexander. George Costanza was neurotic, greedy, and dishonest. Alexander seems well-spoken, charitable and intelligent. (If he is neurotic, greedy, and dishonest in his personal life, he hides it well in public. Talk about good acting.)
Well, George and Jason do have one thing in common. Costanza, as we discussed in his own profile, is half-Jewish. Alexander got both halves covered.
So we are more than happy to add Jason to our list of fine Jewish thespians. Let the goyim have Tom Cruise.