Which particular model of "Dell Quietkey" do you have?
FWIW, Dell used the Quietkey label as late as the black keyboards from the Pentium 4 era.
As with everything else, Dell used various OEMs for various parts of their hardware, the keyboards included. For example, I have three beige Quietkey KBs that all look the same (from the PII/3 era): two are RT7d5jtw and one is a KB-something (IIRC).
The RT7d5jtw doesn't have the roll-over issue you describe (which I'm also well-aware of and really despise), but I don't remember if the KB----- one did or not (didn't get a chance to use it too much yet and it's currently in "deep" storage.) Also, between the two RT7d5jtw's, one has a really nice soft touch on the domes, but the other one is a little harder. They have different CoO's (Countries of Origin). I remember reading somewhere far back that the ones made in country X were better than country Y. But I don't remember much apart from that. From the two I have, the better one IMO is the one with a CoO of Thailand. Either way, both of these are fantastic keyboards for typing and pretty decent for gaming too.
I also have a lot of black Dell SK-8110... or at least they look exactly like the SK-8110. Not 100% sure if they have the SK-8110 model number or something else. Either way, these also don't have the roll-over problem. However, their keys do become prone to jamming after washing with a somewhat strong dish detergent, so I don't like them for gaming as much.
*EDIT*
BTW, if you're looking for a decent rubber dome USB keyboard, the Dell SK-8115 is pretty good IMO. I have several of these too and plan on buying more if/when I see them for cheap again. No roll-over issues as far as I saw, and they are rather durable too.
