Mouse: cheapest, but also most demanding of a clean flat surface and are most likely to strain your hands. Non-optical mice need constant cleaning, and even optical mice can build up dirt underneath that prevents operation.
We can help protect a mouse from the environment (see standard and covered versions below), but, in general, we recommend trackballs.
Trackball: more expensive, but our general recommendation. Many styles exist; try different ones to see what best fits your hand. Optical trackballs are strongly recommended, although the ball occasionally will need cleaning.
Trackpad: common on laptops, but many users find nightmarishly difficult to use. Even if you have a laptop, we strongly recommend a plug-in trackball, mouse, or joystick.
Joystick: more a supplemental device, especially for marking tracks. If you've done video gaming, it may be especially familiar. Not all software supports it.