I have a Mac Plus at home, and the smoothness of the mouse basically feels the same as my magic mouse. I do notice a bit of difference due to the tracking ball vs the magic mouse's laser, but it doesn't seem like the mouse sample rate matters much.

The screen, on the other hand, is much smaller and therefore faster to navigate by mouse. The top menu bar, in particular, doesn't feel like a chore to reach for like it does in modern macOS.