Ask HN: Trackball vs touchpad vs mouse

Hi all,

I've recently (re)discovered the joys of mechanical keyboards, and am looking at optimizing the rest of my working setup. As part of that, I'm looking to try different pointing devices.

Due to their cost, however, it's not easy to just 'try' a trackball or touchpad. What is HN's experience with the latter devices compared to a (optical, wireless) mouse? Are there any researched ergonomics benefits to any of them? Googling mainly results in 'I prefer' type forum and blog posts.

Also, I'm using Ubuntu 12.04, so ideally the device of choice and its advantages should be accessible there...

Thanks!