As expected of Logitech, all the G500's buttons offer excellent feedback, with the main left and right buttons especially giving just the right amount of click. There are 10 programmable buttons altogether: three thumb-buttons, two to adjust DPI, the two main ones, and of course the four-way clickable scroll wheel.
Below the micro-gear wheel is the "scroll wheel mode shift" button, which switches the wheel between notched scrolling for gaming and 'free-wheel' hyper-fast scrolling for lengthy documents. This button was located on the bottom of the G9 - meaning you had to turn the whole mouse upside down every time you wanted to switch - and it's a huge improvement having it back on top where it belongs.
All the G500's buttons are easy to reach, though we do slightly prefer the sideways DPI buttons on the G9 that you could access with your thumb. Also, while the new side button placement is more comfortable, it's possible - albeit rare - to get the G500's three side buttons mixed up in the heat of battle. Putting the middle button lower down and integrating it into the side, as with the superb MX1100 mouse, would have provided a superior solution. Still, overall the G500 performs very well in this regard too.
Like its predecessors and most contemporaries, the G500 has a weights cartridge system to adjust the rodent's heft to your preferences. You get six weights of 1.7g and six of 4.5g in a metal case, allowing for up to 27 grams to be added. As with the scroll wheel mode button, the implementation here is far superior to the G9/9x: you simply press a button in the base of the mouse and the weights cartridge slides out smoothly.
As usual with Logitech, build quality is excellent. Everything, from its springy buttons to its braided cable, makes this mouse feel like a premium product. It's just a shame that Logitech hasn't found space for its response to Microsoft's BlueTrack tech, the Darkfield Laser Tracking system. Like BlueTrack, it allows mice to be used on surfaces (e.g. marble, glass) that normal laser mice can't handle, but its scope for hardcore gamers, with their gaming surfaces, is limited anyway.