The Rock Band 2 & Rock Band 3 Stratocaster are pretty much identical in function, the Rock Band 3 one just features more color variants.
They feature frets that require much more force to press down, unlike the Rock Band 1 Stratocaster. On top of this, the strumbar in both the Rock Band 2 & Rock Band 3 Stratocaster uses reliable magnetic sensors instead of the fragile metal leaf switches, found in many Rock Band 1 guitars.
For other features, they feature automatic calibration with the Rock Band games with some sort of light sensor & microphone inside of the controller. This was not present in the Rock Band 1 Stratocasters.
Wired "Kiosk" variants of the Sunburst Rock Band 2 Stratocaster exist. They feature a reinforced metal USB cable, and are the only wired variant of the Rock Band 2 Stratocaster to exist.
Just like the Rock Band 1 Stratocasters, these are 100% plug-and-play as long as you're using a wireless (360 adapter required) or wired 360 variant of the controller. If you have the PS2/PS3/Wii version of the controller, you need the specific PS2/PS3/Wii dongle.