These comments are meant to be constructive.
i tried 2 Magicstors on my 10D, one from Eastgear (2.4GB), one at Comex (2.2GB). i've also used/owned 3 IBM 1GB microdrives.
10D users, try this: put on continuous mode, squeeze off 9 shots. Half the time, i don't get past this stage. If there's no error, continue holding down the shutter until the camera says 'busy' and will not let you take another shot. At this point, my 10D will hang with the Magicstor - 100% of the time. If you can wait until the LED stops and the camera writes all the data to the drive, then it's a pass.
The above routine has never hanged with my IBM microdrive, so i can only conclude it's the Magicstor. You can try this in manual or Tv mode without any lens, to rule out lens issues. Also use a fresh battery, preferably the original Canon, to rule out power supply problems. Pls let me know if anyone manages to complete/pass this test with the magicstors.
i've also tried copying 2Gb of data to the card using a card reader on the PC. This was ok. Then copy to a laptop via a PCMCIA adaptor - will hang halfway, i suspect, from overheat.
i would really love to love this item, but i think there are still quite a few issues to iron out.