I actually bought the mouse when it first came out, so I have the old revision.
What it means by improved optical technology is that the DPI has increased, so now it compares with a lower model Boomslang. Here are some number I'm gonna throw at ya. A Razor Boomslang comes in two flavors the last time I checked, a model with 1500 DPI (DPI=Dots Per Inch) and another with 2000 DPI. The first release of the Intellimouse had a 1200 DPI, and the newer release has 1500 DPI. Now it compares with the lower model Boomslang, and by my calculations, it's only 25% more 'accurate', not faster. It's only faster in the sense that the optical 'eye' updates faster, which it may. If so, then I'm just running circles around myself...lol🙂 Sorry.
So, for the record, the Boomslang is the champion in precision, but at a higher price, of course.
For reference, a regular PS/2 or USB wheel mouse has around a 600 DPI. If I am wrong about any of this, someone please correct me.