I was running office 2004 and waiting for this. This review is limited but I was looking for specific things.
The good:
-universal binary (faster on intel macs)
-PowerPoint now shows the slides on the left instead of just the text outline.
-you can install it alongside office 2004 and run both versions on the same computer
The bad:
-dragging images from other apps doesn't work anymore
-when you paste an image in word or PowerPoint, it gets converted to a different format so that if you put it back to the original app it's a simple picture instead of an editable one. (for example if you make an illustration in OmniGraffle, paste it in word 2008, you come back a week later and decide you want to tweak it, you can no longer copy the image back to OmniGraffle and edit it. You either must have saved the original or start over. Office 2004 didn't do this and so sadly I'm more productive with office 2004).
-installation is not drag and drop anymore and it installs things like silverlight without asking you. I feel my Mac got dirty now with who knows what installed where.
What didn't change
-you still can't generate motion paths in PowerPoint (to move objects around on a slide) like you can in the PC version since a few versions ago. But you can play this back fine if you generated the PowerPoint on a PC.
-a step backward for me as I want to use it for lectures in my class but now I'm afraid to because I have hundreds of diagrams and illustrations that now will be locked in PowerPoint.
-I'm going to completely use Keynote/Pages (iWork) from now on. Unfortunately some 3rd party apps require Office so I'm stuck with it. And it doesn't have all the features yet of Office.
-Unfortunately OpenOffice/NeoOffice exhibit the same image formating problem and they have their own issues.
Microsoft Office 2008 for Mac Home & Student Edition