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

[Eric Smith]

I wrote a lot of DDS2 and DDS3 tapes back in the day. When my DDS3 drive
broke, I got another drive. I found out that my first drive was seriously
out of calibration, and though it could read its own tapes, other drives
could not. All the data was gone.

I'm considering getting an LTO drive, but I won't do it unless either I buy
two drives, or find someone else with the same generation LTO drive who
would like to exchange encrypted backup tapes for verification.