Can someone explain exactly what the big deal is about the La Marzocco precision baskets and why they produce better consistency?

Are you asking about the Strada baskets? If so, search VST baskets for more info than you bargained for!

How filter baskets affect espresso taste and barista technique is a good place to start; Jim's study covers a wide range of baskets, including the VST/Strada. Searching on "VST" (title only) will yield plenty of opinions, including Scott Rao's Extract Mojo and VST baskets, a perspective from a professional, daily user in response to Jim's study.