For those who were on the scene at the time you'll remember that DVD+R was touted as the ultimate in compatibility that would overcome the 'lack of compatibility' of DVD-R. Many people were sceptical and suggest maybe if everyone used DVD-R we would at least have a 'core format' for DVDR even if the re-writables would be different. It has long been suggested at http://www.dvdrhelp.com/dvd that DVD+R was no where near as good as [primarily] Philips argued and that DVD-R was actually the most compatible format. Now CDR-Info, one of the internet's most respected media sites, have run a comphrensive series of tests with the result of DVD-R achieving 96.74% whereas DVD+R lags behind at 87.32%. The full story can be got here: http://www.cdrinfo.com/Sections/DVDMediaFormats/ So why did we need DVD+R?