Latest IVO died after 3 more months of faithful service. R.I.P. Stopped playing while I was out jogging. This time re-inserting headset to force a power-off cycle did not revive. Player was unrecognized by Windows XP when attached to USB port. So, it is irrevocably dead and cannot even be used as a USB flash drive.
But, even the 3+ months of service I got out of the IVO far exceeds the typical life of far more expensive MP3 players I have purchased. The worst was an Apple iPod which died after just 2 days of use.
Fortunately, the IVO is so cheap (~$15) that I purchased a small supply of them for ready replacements. This should last me for a year or so given the current failure rate.