I've had a lot of bad OIA experiences with the police. Quite apart from the vaguely sinister phone call I got from them once in response, there's the litany of requests "lost", late, or answered with glib bullshit. The police regularly top the list for OIA complaints, attracting over a hundred in 2008 - 2009. Institutionally, they seem to have an attitude problem, an entrenched culture of secrecy which holds that they should not be accountable in any way to the public and that we have no right to know what they are doing.
So its good to see that some of them are doing it right. Over the weekend, I acquired the 2010 OIA tracking data for the Auckland Police District. In the six months to June 31 2010 this district had handled 2279 requests. Six of these had poor data (e.g. typos in dates) so I don't want to guess at them. Of the remaining 2273, only three were late. The median response time was one working day. Its certainly a contrast with Police National headquarters, who in my experience are always late and can't find their arse with both hands.
The real story here is really that most OIA requests to police are routine. While I asked for the information on the subject of requests to be excluded to protect privacy, I understand that these requests are mostly people getting their file for their court date or insurance companies finding out if that burglary happened so they can pay out. While these have always been part of police business, they're technically OIA requests (every time you ask the government anything its technically an OIA request, and they have to help you with it; you don't have to say the magic words "Official Information Act"). And for this sort of stuff, the OIA seems to be working very well indeed.