Well, you can "break" a RAID 1 array and, since it's just a mirror, install a replacement drive and not lose any data. Once you get to RAID 5 you can usually hot-swap and of the drives and also not lose any data.
Unfortunately, with RAID 0, if a drive goes south, you're done! AND, the definitive word from High Point (makers of my RAID controller), you can NOT turn a RAID 0 into a RAID 0+1. I opted for the speed gains with RAID 0 and since I don't feel like spending the $$$ for another 2 drives AND the added headache of rebuilding (again) I'll use my server as the backup system.