The Logitech G5 and G7 are very similar, the biggest difference is, one is wireless and one isn’t.  However there are other differences, like the various weights that the wired G5 comes with.  XYZ Computing has them both, and they can tell you a lot about Logitech’s newest gaming mice.
“Though the idea of a laser mouse is not a brand new one, these products have been making a lot of noise lately. After the release of the first laser mouse, Logitech’s MX1000, not much happened with the idea for some time, then within a short time period Microsoft and Razer released their first laser mice and Logitech released two more laser mice. Logitech’s two new laser mice, the G5 and the G7, are specifically designed to be used for gaming. They have a number of interesting changes from Logitech’s first generation laser mouse. These two mice have a few differences, but are essentially the same mouse in a wired and wireless version. The term ‘gaming mouse’ has come to meant a number of things, including a high dpi rating, the possibility for button customization, a design which is easy to grip, and so on. These mice were designed to handle all the needs of a demanding gaming market.”

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