AppleJack continues to work under OS X 10.9 (Mavericks):
1. Disk repair with fsck is working fine.
2. Clearing of caches both system-wide and per-user is working fine.
3. Validation of plist files both system-wide and per-user is working fine.
4. Clearing of the system swap file, including deletion of the safe sleep image on laptops and desktops that have hibernation enabled is working fine.
5. Automatic execution via both the regular "auto" and deep clean "AUTO" parameter is working fine.
6. Execution of additional special functions, including memory testing via memtest, is working fine.
The only thing that doesn't work:
1. Repairing permissions, and this does not in any way put your system at any risk. It simply fails to start, but then AppleJack continues to operate as normal, including in auto/AUTO mode, going on to the next task.
I would say that despite the fact that this script is "obsolete", and superseded by the recovery partition in Lion and above, it is still a very useful tool to keep in your Mac troubleshooting and maintenance arsenal.
In particular, and I have mentioned this before, but the clearing of caches when in single-user mode is a much more thorough approach than what Yasu, Onyx, TinkerTool System, and other trusted apps provide.
Despite the program being "broken", I'm still giving it 5-stars across the board, and sending out a huge THANK YOU to it's former developer, Kristofer Widholm. He provided us with an invaluable tool that kept our machines in shape for many years.
Please don't consider this blasphemy, but in terms of the larger Apple and specific Mac community, all I want to say to Kristofer is, thank you for your service.