my first scientific calculator was a hand-me-down from my father: a TI-59.  the LED display, cranky card-reader, the ROM expansion, even the fancy thermal printer was quite a powerful setup in its day.

but the venerable 59 was inferior to the HPs made at the time.  while the market began competing on the number of memory "steps," HP was already making more far efficient use of the ones they already had and embraced a keystroke programming model that encouraged simplicity and economy that the '59 only wishes it had.