We're testing a beta of OSX 10.8, Mountain Lion and the initial impression is good. Software update now runs via the App Store (which, I suppose, makes sense) but on our Beta at least, does not update.
Otherwise Google, Office 2011, Adobe CS4 all appear to work fine. Will update on progress later. Not sure about the Notification Centre which opens on the right of the screen... is it going to be essential or one of those 'Dasboard' features no-one uses? The jury's out at FMK.