If you have a special use such as Amergin described, they're great. But, as dick greenhaus says, they're verrrrrry slow (about 20 min to burn a label on my 52x burner, about 6-8 times as long as burning the CD) and, unless you can find the occasional "deal" at Best Buy or the like, quite a bit more expensive. Keep in mind, the label produced is monochrome (black on whatever background color the CD/DVD is).

I've created a few discs, such as a set of mp3 CD's for the car, that I took the trouble to create LightScribe labels for, but, for backup and other casual use, an appropriate marker is my label of choice.