I got a chance to use it for about 15 minutes. After the first few minutes I was rather nonplussed. With 512 MB of ram (an identical matched pair - according to Apple System Profiler) I was hoping for a little more performance. I went to the System Preferences and saw that the processor speed was set to Automatic. I asked the friendly Apple Store Employee if she would be so kind as to change that to Highest.
Boy did that make a difference!
I was truly impressed with how fast and smooth everything felt, from GarageBand to iDVD, Safari to Word. I was amazed.