I love my PowerBook 12", purchased February 2005.
However, I have had it in a number of times for repairs
1. Display brightness uneven (went to repair depot)
2. Airport card connection had to be reseated because the laptop fell on to carpet (quick, in store)
3. New ComboDrive because the laptop, in a lightly padded sleeve, in a laptop bag, fell on to carpet from 2 feet (went to repair depot)
4. I think it'll go in again soon for the same display brightness issue.
I now find out that the brightness issue is perennial (Discussion forum on topic). Weird, and disappointing. Laptops are supposed to be heavy duty, I remember stories about dropping laptops off tables onto hard surfaces and the laptops were supposed to survive unharmed. So although I really enjoy OS X, and the form factor, I'm not sure which laptop I'll buy next time.