If its important data I wouldnt as its software raid and well its always a bit iffy. If it was just for storage of random shiznit then yeah Id give it a go.
Its probably not going to be important, but obviously if I am likely to have issues it would be a bit counter productive -)
Whats the worst that could happen if I was mirroring? Would it be the case that one drives data may get corrupt with s/w raid? Or potentially could I lose the whole lot?
And if say for example one HD goes down due to a hardware fault, there shouldnt be any issues accessing the data on the other drive?