I've just got my application approved. Here's the timeline.
Date applied...24/03/2015
City/Council area... Brisbane
Online / Paper... Online
Date received the acknowledgement email...30/03/2015
Date of the Citizenship Test...14/04/2015*. Approved the same day in ~3 hrs after the interview
Date of ceremony ...............
Type of ceremony (Urgent/Normal)...................
* At first i've indicated on the online form that am going to travel in April, so initial interview date was 30/04/2015. But then i've rang and asked to change to an earlier date as my travel plans have changed.