Just watched two time-shifted pilots tonight, and here's what I think.
Threshold: not good. Did they really need two hours to tell this shell of a story, with clunky exposition and obvious plot twists? And is anyone else annoyed that this lobotomized mishmash of 2001: A Space Odyssey and Darwin's Radio got a green light, while the far more interesting Global Frequency* didn't even sell the pilot? There ain't no justice.
My Name Is Earl: better. Jason Lee is perfect for the title role, and there's plenty of room for the character to grow. But I can also see the series degenerating into farce, as Malcolm in the Middle (and, to some extent, Quantum Leap) did, by allowing the ongoing conflicts (annoying ex-wife, idiot brother, money troubles) and their attendant, more pedestrian antagonisms to overshadow the "A" plots.
* also about a group of experts assembled from various disciplines to solve world-threatening crises