ktchong,
I have used the IntelliMouse Optical extensively, and I like it. My only complaint is when you move the mouse quickly it tends to skip or lose track of its position on the screen, leading to disorientation in a game like Quake3. This is due to the current state of optical technology in mice. The solution in games that I've tried is to increase the mouse sensitivity.
The one I've used is the 1500 samples/second version. The new version comes with "33% improved speed", read 2000 samples/second. I can't comment on whether the improved sample rate delivers.
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It's said that MS IntelliMouse Optical is just too big for people with small hands >>
You're thinking of the MS Intellimouse
Explorer (optical technology), which is a bit on the big side for some people. The MS Intellimouse
Optical was introduced several months after the original Explorer. I think you'll find the size satisfactory, about the same size (but not identical shape, owing to its ambidextrous design) as a standard MS Intellimouse.
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Also, I have heard that its accessory/thumb button is inconveniently located, and it is impossible not to press the accessory/thumb button by mistake once in a while >>
The
Optical has 1 button on either side (for a total of 5 if you include the wheel); I have difficulty pressing the right button (as I'm right-handed, I have to use my pinky), but the left button, using my thumb, is no problem. I don't recall pressing the side buttons by accident. Additional info here:
Microsoft Mice comparison
So I would recommend the IntelliMouse Optical. The MouseMan Optical has a decidely right-handed shape that is also a bit on the large/tall side. The best advice is to try these out for yourself as people have different ideas for comfort when it comes to a mouse. They both have similar features, although the MS Optical has five buttons to the Logitech's four.