- Trackpad: multi-finger gestures. Usually no explicit buttons or scroll wheels detectable by touch, so you need to look down sometimes. Potentially the trackpad allows you to jot arbitrary gestures / glyphs, given proper software. Sits tunder your palm, so you have to move your hand significantly away from the keys to operate it. Good palm rejection is a must.
- Trackpoint: single-finger micro joystick. Sits in the home row, so you can operate it by barely moving your fingers along the home row. Requires explicit buttons; combined with them, usually emulates scroll wheels, etc. Tiny precise gestures are harder. Never bothers you while typing; can be operated entirely without looking, like a mouse.
- Trackball: I have little experience with it. Sits under your thumb usually. Allows for very precise small motions; big motions are harder. Has buttons (see trackpoint), sometimes a larger assortment, accompanied with scroll wheels, etc. Some balls have considerable inertia, some totally don't. Some allow for extremely comfortable hand placement, but it's not a given. Have hard time not being rather tall / thick. Need most cleaning of the three.
I had a ThinkPad i1300 back in 2003 which allowed, in Windows anyway, a thump on the trackpoint to serve as a click. That functionality seems to have been abandoned during the couple of decades I was mainly using desktops and/or MacBooks, because none of my more recent ThinkPads offer it under any OS.
That's a default off option in Control Panel. I'd recommend everyone enable that tap to click feature, sensitivity raised to ~240/255, and middle button as wheel click as must have QoL improvements for TrackPoints.
what are the pros and cons of them? I've only used laptops with trackpads.