Hey Bob, you posted while I was replying to the earlier one.
Hardware compatibility? Well, If you have the hardware to fill-up 500GB to 2 - 3 TB of data in a couple of months or so, you are very unlikely to face that problem. Possibly a new writer will suffice. But just for the record, this particular technology is still not out in the market, and when it does, it won't be for the masses. Now, if you rarely use the disc, it can have a long life too. And besides, you never know which technology performs the best until you try it. Hard drives have been very reliable so far, but who knows when they are over taken by discs? For VERY important data though, multiple backups in different places are recommended. Additionally may be RAID 7?
I think I misunderstood you a little. If you are worried about the discs getting outdated, I think HDD may serve you a little longer. But you do agree that for not-too-important-but-cool
stuff you wouldn't want to take out that drive from your safe and put the junk there?