I appreciated your article on iPhoto 2. I recently switched from OS9 to OSX, at which time I looked at iPhoto 2. I did notice how iPhoto bogs down with large libraries. The article does not mention why this happens, but does suggest how to work around this problem.
My recommendation, not mentioned in the ensuing discussions, is to use Extensis Portfolio, with which I manage a library of over 30,000 pictures under OS9 or OSX. Not only does the catalog not bog down under such a large collection, but I feel Portfolio also provides the various output possibilities which some iPhoto users require.
Another thing I find undesireable about iPhoto is its cryptic method of filing the pictures into myriad subfolders. I much prefer the Portfolio method, which leaves untouched the user's filing system.