I sit here, writing this reply, on a motherboard fake raid that's down one HD. All of my data is still here. It's all still easily accessible and I can keep using this system while I wait for the HD that I ordered to show up so I can get back to full data duplication. It's a very handy feature considering that if I had had the HD fail and wasn't using RAID, I'd be SOL as far as this system is concerned. To those who say that RAID isn't backup, they're right. Making any copies of your data and keeping them in the same building as the original data is also not a backup, as a fire can easily wipe it all out.
For general usage, keeping your systems operable during disk failures, I think that RAID is a wonderful thing to use and I just use the fake raid of the motherboard. On my linux system, I use a software raid because it's easier than getting the system to recognize the motherboard-based solutions. If that's changed by now, then that's great, but it wasn't an option when I built the system.