I picked up my new PowerBook G4 (12inch) yesterday... here are some thoughts (compared to iDucky the iBook).

• It's noticably faster, thanks to the faster CPU, better video card, faster bus, and faster hard drive.
  
• Feels nice and solid like the iBook, and the aluminium skin is a lot more scratch resistent. It's also lighter and slightly slimmer, I think.
  
• Where the hell are the speakers?! The speakers are actually pretty nice for a laptop, except I don't know where the hell they are. I have a sneaking suspicion that they're hidden under the keyboards, although I have no proof...
  
• Dual-monitor support. The iBook supported external monitors, but officially, only supported mirroring mode. This baby can do dual monitor properly, without any hacks.
  
• Slot loading optical drive. That tray was a little annoying sometimes...
  
• Built-in Bluetooth. Who knows... someday maybe I'll find another device that supports Bluetooth as well.
  
• They fixed the display hinge! The iBooks had the annoying tendency to have excessively stiff display hinges that squeaked (or more like, croaked).