I took your advice - but also checked off "swap twist and tilt." I also reduced the scale of pan speed and zoom speed to 0.5.

Feels very familiar now.

However, if you are polar orbiting an object and pass under the ground plane so that you are looking at your object upside down, the twist controls invert... Perhaps intermittently... A right-twist will sometimes twist you to the left.

This behaviour does not occur in 3DSMax.

I will try to confirm this 100%.

;-)