There's also http://www.mdisc.com/what-is-mdisc/ but I've never used/seen it.
Edit: note also, BD-R writers immediately read back and check written data, re-writing damaged sectors to a spare area. This in-hardware defect management should make BD-R more resilient against data corruption than DVD-R or CD-R [2].
[1] https://superuser.com/questions/251369/what-is-the-lifespan-...
In fact, do you remember the very first, early writable CDs? They all were blue on the bottom - that's because they used a metallic dye as well, I imagine 99% of those discs will be perfectly readable today.
I have some myself, but I can't attest to the life span, since I've only had my BDR for about a year now. How does a normal person prove the lifespan claims of an MDiscs other than waiting?
I still find myself burning most backups to 50GB disks, and making redundant copies of only my most important stuff to the 25GB MDiscs.
Where I live, a 3 pack of 25GB MDiscs runs around $20 vs $70 for a spindle of 25 RiData 50GB discs. That's ~6.66/25GB MDisc vs ~2.80/50GB BDR. Not a huge premium for piece of mind, I guess.