The MTBF on both is extremely high. I have the 4Gb Hitachi microdrive for the $/Gb reasons meantioned above. With that drive I can now shoot all my vacation photos in RAW mode for later Photoshop processing. Before the microdrive I would typically fit 200 .jpg shots on a 256Mb CF card. If either one failed, I would lose all the images from that trip.

However, Most of my photography is done less than a day away from home and all I could possibly lose is one days worth of work.

The 4Gb card also makes a dandy way of transfering data of all sorts from one computer to another. 256Mb doesn't cut it for that application.