how good is the data reliability with CD ROM and DVD RAM?

[Carlo Pisani]

hi
yesterday I was shocked by a couple of videos on Youtube where guys
pointed out their negative experiences with CD ROM and DVD RAM as
media for their own backup.

They complained their data completely lost after 5 years of storage in
CD ROMs, pointing out that their CDs were perfectly conserved and kept
clean without scratches, but all the data is gone lost since the media
is unreadable.

This is what they said in the video.

I have a lot of backup here stored in CDs, and I have recently bought
an SCSI DVDRAM unit to create new backups in caddies DVD-RAMs (of
4.2Gbyte each)

what is your experience?