Brent Simmons: On switching away from Core Data.
Brent talks about how he's switched away from Core Data in one of his apps, in favor of using SQLite dirctly (via my FMDB classes) instead. Manton Reece also explains why he doesn't use Core Data as well.
I've never used Core Data in a shipping product because I've been using SQL for ~15 years now and I'm very comfortable with it. And frankly I just don't like the "smell" of Core Data. I'm not sure how else to explain it, but it reminds me of things like EJB. Why doesn't Apple Mail use it? Why did Aperture 3 stop using it?