Larry;
Did you run into this window the first time you updated and closed your iPhoto library?
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I didn't see it on my test library but did on my large, 37,450, library when I started to close it. It took a long time to complete. It only happened on the first run and close. That library is a referenced one. It could be that since the library was so large it just took longer to complete and was noticeable whereas in the other libraries it was too fast to observe.
I ran a quick test of faces in the large library after the latest update and it went rather quickly (with item counts activated). It seemed to be more effective than previously.
I noticed one fix with the new update: the MobileMe galleries now display the photos in all of my libraries instead of just the one that created it. Previously the thumbnails would be blank is those other libraries.
Tim: Faces and Places are quite CPU intensive and require a lot of memory also. How much free space do you have on your boot drive. It may be that the update requires more memory/virtual memory and that might contribute to your slowdown.
OT