the d100 qualifies for sony's fixed-price consumer repairs when out of warranty, while the m1 doesn't. This can be significant if/when a major repair (such as head replacement) is needed, as the fixed rate repair price is less than the parts cost for a new head. If you're planning on x-fering recordings to a computer, the scms issue is a "non-issue" -- it would really only be an issue if you're using 2 consumer dat decks.