The criteria: these are desktop models that I have in my possession. The SR-60, I just had to have: I used to lug one of these monsters around some 20 years ago in Hungary. The HP-85 was a lucky find at a used electronics store, again in Hungary. The APF-231 was our old cat's favorite. And so on...

- Model Type Display Programming model Programming features Memory Special functions
APF 231 APF 231 Four-function 12 VFD digits 256 steps N/A 2 registers Printer, DMS, battery backup
Hewlett-Packard HP-85 HP-85 BASIC programmable CRT 16 kB N/A 16 (0) kB Graphics, tape drive, printer
Elektronika MK-56 MK-56 RPN programmable 8+2 VFD digits 98 partially merged steps Conditionals, subroutines, indirect addressing 14 registers N/A
Robotron K1000μC Robotron K1000μC Scientific programmable 10+2 LED digits 3992 steps Labels, conditionals, subroutines, indirect addressing 242 (0) registers Printer
Rockwell 475P/D Rockwell 475P/D Four-function 12 VFD digits 16 steps N/A 1 registers Printer
Sharp PC-1001 Sharp PC-1001 Scientific programmable 10+2 VFD digits 64 steps N/A 8 (0) registers N/A
Texas Instruments SR-60 Texas Instruments SR-60 Scientific 20 LED characters 480 steps N/A 40 (0) registers Magnetic cards, printer
Texas Instruments TM-990/189 Texas Instruments TM-990/189 Educational board 12 7-segment LED characters 1 kB Machine language 1 (0) kB Machine language educational board