I really think this says more about Costar than Das. I mean, Das should have really tested this more before putting their stamp of approval on it, but ultimately, this is a Costar issue. ABS marketed the M1 as having 6-key rollover, and on certain combinations, it fails miserably. What's more frustrating is that they do make products that work in the Filco line. This boils down to one of several issues: Costar doesn't seem to get the requirements right in product design, they implement solutions in a slipshod manner, or they do not test well enough (or some combination of the three). Of course, the only people that suffer are the consumers. I guess the other aspect of this that frustrates me is that there doesn't seem to be any pressure from the distributors (Das, ABS, etc.) back on Costar to get these issues fixed. In the case of ABS, it seems they rolled over and removed the claim of 6-key rollover. I would imagine some of these companies would want to preserve their good name, especially small companies like Das, so when new version x comes out, customers would have been happy enough with x-1 that they want the new version.
/rant