I confirm they work fine, when they are handled carefully and correctly.
The SD slot of the Zaurus is a but dangerous: If you put in the card and don't press firmly enough, it pops out again (because it doesn't rest). But it had contact already and Linux may have mounted the card partially. This can lead to data loss on the card.
Using MiniSD adds another similar mechanical weak point.
Also, one of my test cards in Mini SD format did not work, because its Mini-SD/SD adapter didn't fit the Zaurus correctly. I had to press with more force than normal in order to put it into the Zaurus SD slot. Afterwards, I didn't get it out by pressing anymore. I had to pull it out using pliers.
Afterwards I had to put in a normal SD card and press to get it out again, until the slot worked normally again.
So be careful!
daniell