The biggie for me is auto diagnostic software to go with the USB-OBD-II cables I have. Even given that, I am thinking about buying a Mac Mini in the near-ish future. Just waiting for the new chip stuff to sort itself out.
I’ve been using ‘Torque’ on the phone with Bluetooth. Happy with it. Only consumer-level ODB-2 diagnostics but very comprehensive.
I have a Bluetooth OBDII device. Can talk to it with my iPhone.