I use a Nulea trackball and a Nulea keyboard. I bought two of the trackballs. The previous trackball I had, the scrollwheel was dying too often (for $60 it was kind of annoying) and the Logitech MX trackball, eventually the switch for clicking dies, and replacing it yourself is more than just a 2 minute task, not worth it for me).
I prefer just having two trackballs, especially since they don't move, they're very ergonomic. The keyboard is the style of a Microsoft Ergonomic Keyboard, but it supports multiple devices. The keys are exactly how I wanted them (flat), and its been a good keyboard, supports one USB dongle connection, and two bluetooth connections, which is what I wanted. I was surprised how good the keyboard is after passing on it on Amazon a few times, which led me to try their trackballs, and I was not disappointed with either purchase.
I prefer to just hard switch the keyboard, so I don't get confused as to which computer I'm going to be typing on, sometimes I switch computers to google something personal that I rather not type on a work machine.