The X-plorer controller was packaged with the Xbox 360 port of Guitar Hero II. The X-plorer is very different from the SG, the PS2's controller. It is much larger, much heavier, and the buttons stick out further from the neck. It can be used any guitar music game on the Xbox 360 or PC, including Guitar Hero II, Guitar Hero III: Legends of Rock, and Rock Band.
Some Guitar Hero players dislike how skinny the neck is compared to the Les Paul Controller, while others find it more comfortable. Most of those who prefer the Les Paul played Guitar Hero III first, however.