Interesting. I'll see if I can snag a copy, at some point.
In my own experience, I tend to agree that things are usually caught pretty quickly (minutes), after a few days or weeks, or essentially never. The "regular" RC patrol and anti-vandalism bots are excellent at catching sudden and large changes which are obviously problematic, but more subtle changes usually get caught by editors diligently checking their watchlists for articles they've worked on or particularly care about. In my opinion, anyway.
Problems can come up, when two vandals hit the same page, whether in quick or slow succession; if the first change is subtle, and the second is blatant, then more often than not a bot or RC patroller will revert only the later change, and will neglect to even check the first. We need to encourage people to check over the pages they revert, to see if they may have missed any lingering vandalism.
Speed is good. Our main advantages, in my opinion, are in numbers and tools. We should use them to our best advantage. Increase awareness of tools, even just of page history, user contribs, and the ability to report vandals, and even common laypeople can help us keep things clean.
I personally am interested in two main areas, here: improving our mechanisms to help experienced users detect vandals, and educating the public as to the available tools and options for dealing with vandals.
Bit of a ramble, I guess. I keep telling myself I'll provide some useful coding, once I have a bit more education in that area, so hopefully I'm still involved with WMF when that day comes.
-Luna