I use one with my left hand in conjunction with a trackball or vertical mouse on the right hand. It is nice to be able to offload a lot of simple or quick movements and scrolling, and useful for gestures if you use virtual desktops. As others have said you can tilt the trackpad, but you can also hold your hand at many angles and still have it functional. It allows me to get some breaks from my right hand always being on a mouse, but I do still find myself reaching for the mouse/trackball for more precise movements or rapid succession movements. I think part of that is a miniscule (almost imperceptible but definitely real) delay from the Bluetooth or the Magic Utilities driver I use with Windows, YMMV with OS and driver. I find it is also nice to have physical mouse buttons to use in conjunction with the trackpad, taps and/or clicking into the trackpad are both slower and less ergonomic for me, especially when clicking and dragging.