Their's 2 format: the DVD+R & DVD-R
They are not compatible.
This is a good article on the subject:
http://www.idvd.ca/dvd-format-guide.htm
It take about 45 minutes to burn a full dvd...
If you are looking for a burner buy the only burner that could burn both formats: Sony DRU500AX
http://www.sonystyle.com/is-bin/INTE...E_KQN&Dept=cpu