Hmm, I saw that same acrylic cutting tool but neglected to pick it up. Does it cut better than a utility knife?
Lots of people have mentioned this already, but I found it most helpful to drill acrylic by first starting the hole a little ways, then switching the drill to reverse, and then switching back to forward and finishing the hole. It seems the middle step, running in reverse, helps to warm up the acrylic before you make your final cuts. This method worked really well when using a spade bit to cut holes for joysticks and buttons.