I worked for the Department of Environment, Land, Water and Planning for 2.5 years. I started as a Policy Officer (VPS 3) and moved up to a Senior Policy Advisor (VPS 5) during that time. The general working culture was very positive, access to professional development was great, and colleagues really care about what they do.
I worked on three different teams during this time. My advice to job seekers is to get hired in whatever job you can get, as there are great opportunities to move across and up within the organisation in a short amount of time. As with any large organisation, it is very important to question people who work in the general department about the specific team that you are thinking about joining, as culture, competency, and management quality/style varies greatly.
Important work, great people, great benefits (salary, access to training, flexible hours)
Internal politics of large organisation, some experience with poor quality management