arawnsley: I've always felt that, like banks, hard drive brands are very personal things. Some people hate brands that others love. Out of the hundreds of drives I've ever owned, only one has ever failed while actually in use. And it was 4 years old, so frankly fair-game. And it didn't die in a way that made all the data on it entirely unaccessable, so a backup of most of the data was easy.
However, I know people have hard drive failures monthly. I have no idea how they mistreat them. However, I've always kept lots of space between drives, and had plenty of cooling. I never put drives in plastic cases, only metal ones. I replace drives every three years, mainly because I need more space or faster access by then, rather than replacing them on reliablity grounds, of course.
RISC OS does put somewhat more strain on hard discs that other, more modern OSes, however, due to its lack of caches: read caches prevent the load on the drive for commonly-accessed stuff, and write caches allow you to intellegently order writes to the drive thus reducing how much work the drive has to do. Perhaps this is a situation ROOL can help with.