My local bike shop is was started by some famous cyclist dude, who's son, an ex track bike "star" (who now runs it) stocks both the KMCs and the Izumi Super Toughness. When I needed a new chain I went in and asked his opinion. He told me the people in the Olympics were using Izumi's, but didn't think I'd need one. He assured me the KCM 710 I got was a proper "track chain". I've been using it heavily for months and I can't complain about it.

But then again, this might be a bit loopy. He installed my 2nd sprocket without a lock ring saying he's never needed one on one of his track bikes: "And I used to race bikes 50 mph!"