There are a lot of ways to approach burning discs. Burn keeps it simple, but still offers a lot of advanced options. Create data discs with advanced data settings like, file permissions, the disc icon, file dates and more on the fly. Create video and audio discs without worrying about conversion. Create your personalized DVD-Video discs using themes. Recreate discs and disc images you all ready have. Burn doesn't reinvent the wheel, it uses many powerful open source Unix utilities and is also open source.
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It's better than the default burning options you get built into Mac OS. I tend to have to burn slower or I will get more errors than on something like Toast, but for free, this is the best option. No frills, but handles video, music, data, and disk images.
According to Wakoopa, it's on Windows too. I didn't see a link nowhere.
best open source no frills burn tool out there