I would love either one and be happy with either. Im sure both are great and anybody that had either one would be more than happy with their purchase/item.
iPod
*Nice to have most/all music on one device, no swapping, nice and lazy
Hi-MD
*Security, iPod crashes you got nothing. Hi-MD crashes you simply exchange it for a new one (hoping you purchased the extended warranty).
I would go with the MD anyday, lil cheaper and just safer in my opinion.