The G9 is an amazing mouse. I have smallish hands and use a claw grip and the G9 fits me like a glove. I wasn't much of a fan of the G5 because it's more of a palm grip style (large surface area), but for me G9 all the way.
Some people think that the high dpi on gaming mouse is overrated. Let's put it this way. If you use a mouse with low dpi, you have to raise the sensitivity in software (windows, games, etc) to boost it, especially at high resolutions. It places a scaler so the higher the sensitivity the less responsive your mouse. If your playing a fps your accuracy is directly related to the scaler that the sensitivity setting uses.
If you get a high dpi laser mouse, you can raise the mouse dpi and lower the software sensitivity, which gives you much more accuracy. An arbitrary example would be that with a low dpi mouse, you might track 1 out of every 20-25 pixels whereas with a high dpi mouse you can track 1 out of every 3-5 pixels at the same cursor speed (no realworld numbers were used in that example). You can immediately see the advantage.
Lately software has been using something called "cursor smoothing" to help compensate for lower dpi mice (it lowers sensitive for small movements), but too much and your movement feels mushy.