The first time I defragged it it made a horrible clanking noise and I was sure it was going to die in the next few minutes. I posted [link|http://z.iwethey.org/forums/render/content/show?contentid=15789|here] about it (I still haven't installed the Seagate replacement.).
But that was well over a year ago now....
It's been fine and subsequent defrags have been quiet and uneventful. I keep an eye on its S.M.A.R.T. parameters with [link|http://www.almico.com/speedfan.php|SpeedFan] and so far it looks fine.
But the 8 hours on-time and so forth do cause me to worry about the reliability of drives these days.
Cheers,
Scott.