This worked for me and my colleagues:
I was forced to spend some of my precious time looking into this use today and I have now worked it out. The command that everyone is using is correct, but there seem to be some new plist caching being used in Mavericks that is being messed by by the "killall Finder" command. The key is to reboot rather than killall.
To show all the file:
Type the following into a terminal window:
defaults write com.apple.finder AppleShowAllFiles 1
Then REBOOT. Do not use the killall Finder command as suggested in other posts.
I got the clue from this post:
http://hints.macworld.com/article.php?story=20130908042828630
What we can see happening is that then we run the defaults command, the finder plist is updated correctly but when the killall command is issued and we recheck the plist, the AppleShowAllFiles line is gone again. I figured that the kill all command must trigger some kind of security in the OS. It probably thinks that Finder has crashed and it refreshes it's plist file from a backup. I guessed that a reboot of the system would gracefully write any caches to where they should be. This seems to be the case.
