there may not be hard data to confirm that newer generation drives have problems, but ask anyone over in the planet replay forums about using the early diamondmax 10 & 9 drives in their dvrs. any new generation technology can have unforseen bugs that you can end up being the statistic for. if you really want to play it safe, & have a larger drive, you can always get the extended warantee if it's offered. if you can get a 2 year warantee on a drive, it's likely that by the time just a year or so has gone by, the drive has undergone 2 or 3 revisions in firmware at least. if you have a problem with it & have to send it back (i've had to do this with both maxtor & seagate (SATA II & ultra320 SCSI respectively) & the new drives that they replaced them with were either several revisions up from the original (maxtor) or physically a whole new series drive that was the same basic size & model drive (it was the same size cheetah drive, but half as tall physically & a whole lot faster, quieter, & surprisingly cooler running). i usually run my drives 24/7/365, and honestly, i've only really had 2 drives ever fail on me (because i usually end up upgrading before they fail). if i run a drive more than 4 years, it's only because i end up handing it down to someone else in the family.
to play it the safest though, look for a drive that's been out for a bit, yet as large as practical for the $. if it's been out for 6 months, & is still selling like crazy, (and you haven't heard big mobs of people having problems with it), it's likely you'll be ok. the thing is, it seems a bit foolish (to me) to buy a drive of say xxx size, when you can have a drive half that again or more for like $20 or $30 more. if computers have shown a trend, it's that operating systems & file sizes, and total files, keep increasing...... so you really can't go too big in that respect.