1. You have no reason to have the Lion GM.
2. It doesn't work on all older machines. Such as the Early 2008 MacBook Pro family. If you had a reason to have the Lion GM, you'd know that.
3. Buy a newer machine.
1. I do have a reason to have the Lion GM because I am a registered developer
2. People have reported having it on the machine that I have (2008 MacBook plastic, white)
3. I don't want to shell out another $1000 just for one feature