I've been using iPhoto Buddy since about Version 1.1 (at least 5 years). As an educator, web-rookie; designer; animator; (among the many hats I wear using digital photos), I use (or support others using) several versions of Mac OS X and of iPhoto/iLife. I encourage all my clients and students to use iPhoto Buddy.
I am still in awe, with every iP update that Apple hasn't taken up this idea. Those of you who prefer to quit iPhoto, reopen holding the option key, and then browse for your other libraries each time you want to change -- more power to you, but I much prefer to have my list of libraries in one place from which I can relaunch the iPhoto library I need in one step. I have several different categories of photos -- Family shots; Professional photography; school yearbook client website photos; stop-motion animation libraries; to name a few.
Moreover, without having to open each library, I iPhoto Buddy shows me exactly which albums, books, slideshows; how many "items" (pix & movies); which iPhoto version; etc., etc.
Don't know how I'd function without iPhoto Buddy!
Thank you for keeping it freeware. I encourage all to donate.