I think it's more luck than anything.
The most obvious problem people have been getting is the extreme vibrations.
I suspect that the drives are okay during QC, but during transit, all the crazy van drivers are banging the drives about and knocking that little plastic part out of whack which so far seems to be the problem.
It wouldn't be unreasonable to wonder if the rest of the drive is that 'delicate' too, and as someone has already said the build-quality of the 716A has not been great...
I haven't opened mine up (No point in voiding the warrenty when they have such good RMA services!), but for the price they're charging it would be cheaper for THEM to go that little bit further and just make the whole thing more 'solid'.
The thing is, the drive works fairly well despite the vibration problem on mine, although I'm getting rather high error rates on Verbatim -R media (150+!), vs their +R media (~4). Given what little I know about -R vs +R, it wouldn't be too big a stretch to put spme of this down the the vibrations...
I'm now awaiting my third RMA... hopefully they've sorted things out by now...!