To re-iterate, for the sake of all those who do the same thing
    as I too have done in the past:

    "Reliability degrades when they are operated in low-impedance
    circuits, and so they are not suitable for power supply
    reservoir operations".

    ref, p 83, "The Circuit Designer's Companion", Tim Williams,
    1996, Newnes pub.

Really?  I see them used this way constantly, even recomended (particular
brands and values, usually) in SPS chip app notes, and advertised for this
purpose (ie by ESR, IIRC.)  Are SOME tantalum caps specifically (re)designed
for such applications, or are some other specific types (perhaps no longer
very common) the ones that are unsuitable there.

(come to think of it, I don't know that I've ever seen tantalum caps widely
used for anything BUT power bypass...)

BillW