Excerpt: Works perfectly with Win XP and Win Vista BUT "button 3" does not function as a "double click" button when used with Microsoft Word and/or Excel and Windows 7 operating system. Spent an hour with Logitech tech support - they actually went into their lab and tested the mouse with Word and Excel and verified - button 3 works with XP & Vista but is non-functional with Windows 7.
Summary: Although I generally really like Logitech products and appreciate their attention to product quality, I was a little disappointed with this trackball for a number of reasons. Compared to the similarly priced Kensington Orbit or a typical mouse, this is quite long and it is difficult to properly ground your wrist behind it. It does depend on your desk setup to some extent but it can be uncomfortable to use in some circumstances.
Summary: This is the second Logitech model mouse I have bought in the last couple of weeks. Neither of them will work on Vista Home Basic either with or without the software provided and on Logitech's website. They both work fine on XP, so I have kept one for my desk top and given one to my daughter. Unfortunately, Logitech seems to be the only manufacturer of trackball mice now, but have offered no help.
Summary: I own both this "Marble Mouse" and the "Trackman Wheel", and definately wish i hadn't bought this one. Undoubtedly good build quality etc; logitech have trackballs to a fine art. But the central ball, operated by fingers, has a far less accuracy than does the other product's (which amazon also sell) thumb-operated side-mounted trackball.