1. Leaving an SD or CF card in the unit drains the battery, even with it powered off. Leaving both cards in drains it twice as fast as one.
2. Leaving a CD card in the unit may cause it to disappear when the unit is powered on. Restoring the card requires a soft-reset.
3. Leaving an SD card in the unit may cause it not to turn on at all if the battery is below about 85%. Removing the card allows the unit to turn on normally.
4. Frequent error messages regarding GWES.EXE, a core Windows file that handles the graphic user interface.
5. Setting the unit in the cradle with it turned off may result in the so-called "White Screen of Death"; the screen turns on solid white and the unit becomes totally unresponsive. A soft-reset is required.
It's been confirmed that this is a problem with Dell's ROM image, not a hardware problem. It affects both the X51 and the X50 upgraded to WM5. Dell claims a new ROM image will be available on the 18th. I don't know how they're going to handle this for X50 customers.
I've also learned that the version of ActiveSync Dell shipped with the X51/X50-WM5 is a Developer Release, not a final release version. The final version isn't even available from Microsoft yet.
So much for Dell QA.