I could never get into iPhoto. I didn't like/trust OSX "managing" where my pictures were stored. Lightroom has a catalog too...but your photos are stored wherever you desire and the catalog reads from wherever you initially establish your photo storage.
My pics always reside on an external hard drive. If push comes to shove, I can connect that harddrive to anything and go directly to a picture independent of Lightroom. iPhoto wouldn't allow for that.


"Get ready....for your blessing....."