Across all the Office programs, there is a new, softer look that subliminally suggests you can approach the new system comfortably. That new friendliness is true across all the applications, from the Outlook email program through Word, Excel and PowerPoint (the only applications I'm currently evaluating in Office Professional). This right-brain improvement in all the applications isn't something you'll see in feature checklists, or if you do it may sound like marketing hype. But seeing is believing.
On the consistency side, one of my past pet peeves with the Office suite was inconsistency. If I created a table in Word and imported it into PowerPoint, or vice versa, I'd always get something different. And if the direction was from Word to PowerPoint, I'd get a "dumbed down" table because that's all PowerPoint could handle. Now I've found that you can create complex (and beautiful) tables in PowerPoint with all the horizontal and vertical cell merges you want, and export them accurately into Word. Not only the power of the new table model, but this consistency across applications, is a very strong inducement to work with the new Office 2007.
Now it is Sunday evening, and it appears I spoke too soon about how well PowerPoint uses styles and its consistency. It appears that if you have existing objects (e.g., bullets) and change the bullet styles via the master, it doesn't apply those changes to the existing bullets, only to new ones. In fact, PowerPoint Help confirms this: "It is a good idea to create a slide master before you start to build individual slides, rather than after. When you create the slide master first, all of the slides that you add to your presentation are based on that slide master. However, if you create a slide master before you start to build individual slides, some of the items on the slides may not conform to the slide master design."
Thus IMHO, PowerPoint styles miss the point: A truly styles-based system would let you change your mind about the look and feel of a particular kind of object, then apply your change to all the objects of that type.
One last observation: Your editing view of PowerPoint slides, where you can see and edit the objects, is called "Normal." Why not "Draft," since Microsoft changed the name "Normal" to "Draft" for MS Word. Another inconsistency. Naughty naughty.