Works Just fine...formatting was a pain.
I purchased a 64GB Sandisk SDXC from Amazon on special sale at $49.99
When it arrived plugged into the Xoom and it didn't want to know.
I tried formatting using Windows Vista to Fat32 and exFat no joy. Tried using numerous partition utilities. I either got 27Gb or 1MB??
I searched the Web and it seemed from others experience to be a hit and miss affair. It stood to reason that a phone should be able to do it as some people had already confirmed.
I tried a Motorola Droid - No joy
I then used my HTC One X - perfect. I put the card in, did an unmount/erase/mount and it registered 58GB free.
I have the original Motorola Xoom WiFi 32GB running 4.1.2
The HTC is running on Android 4.0.3
Neither are rooted devices they are stock.
Happy bunny..just remains to be seen if it runs stable. No reason why it shouldnt. I can now increase my onboard music library and have room for apps and video.
Oh worth a mention....
Once installed you only have read access from the Xoom as stock. I downloaded and app SDCARDHD from the Play Store $1.49 that allows all the functionality of copying, pasting etc. Worth the money and something Google should address as this is pretty basic stuff.