I have an update regarding the use of the KEEN Commuter sandals on the HooDoo 500 Ultradistance Bike Race by my husband, Russ Stevens. He returned to the event in 2010, as a Voyager (no support crew or vehicle), and finished the event in just over 40 hours. He did buy a new pair just before the race, as his originals were a getting a bit tattered. Here is a LINK to his ride story.
It was an incredibly tough field out there. Russ broke the current Voyager course record by 2.5 hours, but still only came in third! He definitely fielded lots of questions about his footwear!
(also a KEEN fan, but only up to 250 miles at a time so far!)