I will say that I've had similar experiences. I wouldn't have a pi that does a large amount of reading/writing for a mission critical task. I have one pi, that I'm not sure if it's a hardware issue or what, but I've got to the point of just restarting it every 6 hours, if I don't, it hard freezes.
I've also already ruined one (admittedly, cheaper no name brand) SD card on another raspberry pi. That one went after 2 weeks of hard usage. I now have an ever growing collection of SD cards (4 gig cards are too small for more than basic uses of the raspberry, even 8 gigs can be a bit limiting)
That said, the raspi's are fun, but I wouldn't trust the SD cards on them with something like this.
I've also already ruined one (admittedly, cheaper no name brand) SD card on another raspberry pi. That one went after 2 weeks of hard usage. I now have an ever growing collection of SD cards (4 gig cards are too small for more than basic uses of the raspberry, even 8 gigs can be a bit limiting)
That said, the raspi's are fun, but I wouldn't trust the SD cards on them with something like this.