Disc Burner isn't powerful enough for many of us, nor does it offer the important features that keep us getting Toast. For one, I need to be able to make bootable cd's, fast and easy. Toast does this in a snap, where DB cannot. With Toast you can skip the verification stage, you can't with DB (doubles your burn time).
Yes, you need to purchase Toast (this site doesn't support warez at all), but it is a worthy investment.
All in all, DB might be ok for the light user, but any of the power-users get Toast. It does the job, and does it very well. It can even write to dvd-rw disc's where DB cannot. Toast also handles cd-rw and multi-session burns very easily. 😛 😀