<font face="Verdana, Arial, Helvetica, sans-serif" size="2">Originally posted by bollar:
FWIW, I had a 340Mb Microdrive fail on me and I decided that it's not suitable for a mobile application like photography. </font>
The early 340Mb IBM Microdrives are known to have problems. Current Microdrives are as reliable, or more, than solid state and faster.
If you want anecdotal opinions, I had a 256Mb sodid state CF decide it didn't want to give me my images. I finally managed to convince it to yield, but still...