OK, good idea, bad implementation, poor performance...
What they should have done instead was simply have you connect it to the molex connector, and use a very short SATA cable to connect it to the board. Strapping a small SDD to your cable bundle is a better idea than leaving a leverage point sticking up out of a cheap plastic SDD slot, those connectors are not designed to handle stresses of having a compponent sticking out of them like that, and they're too small to properly accomodate a drive without blocking ports...
Further, with Visat, anything less than a 64GB main drive is dumb. I though a 32GB partition would be fine, nearly double what I used for XP. Afterall the install was only slightly bigger. Nope, Vista puts so much crap opn C: in hidden directories, that over time, it grows DRAMATICALLY. Some of it can be moved, but it;s a real pain, and many applications don;t like it.
For Linux, sure, 8-16GB might be fine, even OS X would run nice in a 16-32GB partition, likely XP too, but it's too small, too expensive, blocks ports, and worst of all doesn't actually offer a dramatic performance advantage...
If they were thinking diagnostics, it should have been an esata drive...