Yeah, I've seen things go horribly wrong too many times (being basically San Antonio's equivalent of the genius Asian kid down the street who can build a Cray from a cereal box) - not even counting, of course, the people who've dropped, kicked or otherwise shocked the things and wondered where that whiny noise, smoke, and complete and total data loss came from, I've seen problems with slower computers not being able to keep up with writing data too many places (24-bit/96kHz puts more stress on computers than people often think, apparently), unstable power supply issues (it's a lot easier for an external to get less attention than it should, there are simply more things that can go wrong with an external - of course, that's more of an issue with USB drives, but when I see peripherals get ignored for one reason or another it's long before internal hard drives have problems), and more massive failures of externals than internals for no apparent reason whatsoever. I'd just rather use the fucking tank-built monstrosities that go in the box (because I've been using them for sixteen years) than the gizmotrons that popped up a few years back that were designed for convenience and ease of use... forgive me for having used computers WAY too long to trust new stuff that easily. It's just far safer, judging by my experiences with both types, to record to an internal (which I experience to be far faster and better able to handle oddities and glitches, and which I can control much more easily with the disk tools that I've been using since before your computer store clerk knew a Serial ATA from Satan) and back up to an external when things aren't quite so... 'mission critical'.
Jeff