"the great HP28 fiasco "
I note you have the HP28S .. my dad got me its precursor, the 28C, on a visit to the US in the late 80s. .. following which, HP realized that 2K memory was just not good enough to do decent numerical (let alone symbolic) differentiation/integration, so they upgraded the 2K to 32K, which became the 28S. There is no other difference whatsoever between the 2 models AFAIK.
So here I am, still using the 28C .. and getting 'insufficient memory' messages whenever I try anything a little too ambitious .. also I also use an even older trusty 15C. And they're really not a lot different from modern calculators in what they do. - Apart from RPN of course, which I like a lot as I'm used to it.