Design and Features
The shape of the G603 is nearly indistinguishable from the G703. It’s got the same generic, mid-profile curve that works fairly well for those that prefer a palm grip and those who prefer a claw grip. It’s made exclusively for right-handed gamers, with the thumb buttons on the left and a gentle slope down toward the right side. It’s comfortable, but a little generic.
The left side features a pair of buttons that I found easy to reach with my thumb, and have a good click action to them. You can execute those additional gaming commands without pressing so hard the mouse moves around, but they’re not so sensitive that you’ll activate them accidentally.
On top is a scroll wheel and a single button (by default set to cycle through DPI settings). The wheel has a nice wide rubbery grip and a clicky scroll action. The left and right buttons have a nice audible click to them, with firm actuation force well-suited to a variety of games. But those who like really short-throw, soft-touch action for extremely rapid clicking (like RTS pros) might find it a little on the stiff side.
The G603 is devoid of any lighting, unlike most of Logitech’s other gaming mice. The whole point of this mouse is its extreme battery life, and lighting drains the batteries quickly. Whether the lack of RGB lighting is a benefit or a drawback depends on your individual taste.
The top shell is held on with magnets: inside you’ll find space for a pair of AA batteries and a little slot to stow the tiny USB radio receiver when you're traveling. The receiver is optional, by the way. The G603 also works with Bluetooth, though you don’t get top-tier gaming performance.
On the bottom you’ll find a switch to toggle the mouse between “Performance” (1000Hz report rate) and “Endurance” (125Hz report rate) and a button to flip between the faster LIGHTSPEED wireless receiver and Bluetooth. What you won’t find is a door to pop in the little round disc used for Logitech’s POWERPLAY mat. That accessory is made for mice with sealed, rechargeable batteries, not removable AAs.
The G603 uses the same Logitech Gaming Software that works with all its other peripherals, and has the same essential features (minus RGB lighting) as the G703.