how good is the data reliability with BD-R (Blu-Ray)

My BD-R story: For a little bit I was trying to go Blue Ray for backup of conference talks I was recording at the time. I picked up a Samsung BD-R drive and some memorex media. The media for BD-R comes in a High to low and low to high versions. One is dye based not for long term, the other type is long term. The Memorex type I got was the long term type. I carefully made 2 or 3 copies of each set of video files. Each event took 2 to 3 discs (Was recording events live using Blackmagic ATEM system, 5GB per hour is the data rate in 1080i60 h264 encoded.) After about 9 months I went to copy some data back. It was all gone. Everything deteriorated and all the data was unreadable. Before I bought the drive I looked for info on reliability and didn't find any indicators that the media sometimes has severe issues. Since then I kind of swore off optical media. I have some Verbatim discs but I haven't used them yet. I figure they will do better, but still bitter over losing the information from the earier events. I have around 60TB of spinning disks at home, but will be going tape in the future. A lot of my data is conference video and backups of laser show tapes which often are 8 channels of WAV data @ 48khz, so ~3-4GB per 30 minute show tape.