You can download the driver without buying a new mouse (or lost your disc). I've plugged in Logitech mice with Microsoft Mouse installed before and it still seemed to work fine. http://www.macupdate.com/app/mac/29220/microsoft-mouse
I think the complaint in this article is laughably petty. I've never noticed a lag. But on the topic of mice, I bought a Kensington mini-mouse about three years ago that I've used with three different laptops (2 Macs and a Thinkpad) and to this day I've never noticed a difference between any of the computers. I would recommend it just for its size and functionality, it's the best mouse I've ever used. I didn't even have to install a driver for it, it just works immediately when I plug it into my Pro. It does feel faster than the trackpad but I think it's just because of the nature of trackpad vs. a mouse and not because of any noticeable lag.
