Looks like the upgrade has gone without a hitch. The mobile theme works anchors a weigh!
I have now messed around with WP 3.1 and so for so good. I can however report that the site is a little messed up in Chrome 10 beta. What i mean is that when scriolling up and down the images or content dont always scroll smoothly. I have noticed this on my laptop mostly (which is a new machine) . However this is not a problem in Safari or IE9 RC. This is most likely a function of Chrome rather than WordPress. I am bit addicted to Chrome as I was to Firefox when it first appeared, so I am always using the beta versions with the risks that associated with beta releases.
All my plugins are happy but I cant really say that I have pushed all the new features yet. I would like to the media gallery upgraded as I find it a bit clunky. I am no html wizard so I guess that I will wait for the forthcoming releases.
The other issue I have had is with video uploaded from the WordPress app on my iPhone. Here Chrome and Safari shine but not Internet Explore 7 or 9RC. The video sample is here I have used the new internal linking feature of WordPress here.