Yep, they get a puke smell after a while.

In almost all cases the final 2005-2006 models are the most reliable across the board. But it depends on the size you want and what you want to do with it, TBH. The final iBooks have more RAM than the 12" PowerBook (though correspondingly less VRAM). That being said most PowerBooks aren't too hard to get open. The same cannot be said for the iBooks.