LVM? DM-RAID? Both? None?

Patrick tells about his experience moving from LVM to RAID.Now, why do this? I have two machines set up with LVM-based mirroring, and they work like a charm - I even think they work with better flexibility than setting it up in a RAID-controlled way, as each of the partitions in a volume group can be easily set to use (or stop using) the mirroring independently, and the requisite of having similar devices (regarding size) also disappears. Of course, this flexibility allows you to do very stupid things (such as setting up a mirror on two areas of the same rotational device - Good for toying around, but of course, never to be considered for production). And the ability to online grow and shrink partitions is just great.

So, Patrick, fellow readers, dear lazyweb, why would you prefer LVM-based mirroring to a RAID alternative? Or the other way around?