It is certainly an upgrade over using a standard keyboard with gaming! Buddy of mine is left-handed and has no issues using the nostromo with his left hand. There is a thumb stick that can be used for movement (emulates arrow keys). I use this device for StarCraft 2, World of Warcraft, and Diablo 3. The hotkeys are wonderful and once you get used to having this, there is no going back.
It's designed for use with the left hand. It's not reversible (which would have been awesome design). You can use it right handed. It's not quite as ergonomic. In that position it's also missing a key that your pinky would use. Instead your pinky would hit the scroll wheel.
The Nostromo is not a mouse - it's designed to replace the keyboard with a designed-for-gaming movement and keybinding device. It's meant to be used in tandem with a mouse in your right hand. I've been using this setup for several years for numerous game types, and find it to be far more ergonomic for extended gaming. The Nostromo especially shines for MMORPGs, where WASD movement complicates using the large number of available abilities.
For the casual PC gamer, this device might be overkill.