RAID 1 is good - I have no problems with anything in RAID1 (other than RAID5, for example, being less wasteful..)
RAID 0: If ANY drive in the array goes down, you're hosed.. the chances of you losing data skyrockets. As far as planned obsolescence goes - I'm referring merely to the expected lifetime of an IDE hard drive, barely longer than the three-year warranty it comes with. I'd never trust an IDE drive over 3 years old with my data - a 10-year-old SCSI drive, built like a tank, I'd trust.
-A