I had a TI-86 and then won an HP-48GX. At some point the TI-86 was lost or stolen, I don’t care, the HP-48GX was so much better. I especially liked working with units, which made everything in science classes that much more convenient. The only thing I missed about the TI-86 was the Mario clone, with level editor, and a puzzle game called DStar.
While the TI-83 and 86 had a pedestrian Z80, the HP series apparently had a weird nybble-serial architecture called Saturn that worked on 64-bit values.