In my experience it seems to matter where you live and if you are renewing an existing policy. I used CIL on my old KK for 1 year, their renewal had a hefty "lazy tax". Moved onto AAMI.
Each year I do the ring around of the majors, for my Vista XL AAMI have been the cheapest premium for the past 2 years (I have a house and contents policy with them so that helped the price). However, on insurance for my GU Patrol, 4.2l diesel, Coles was by far and away the best, cover all my accessories and the agreed value is $20,000 higher than Club 4x4 would "agree" to, TCIS wanted my first born + to insure the Patrol for about 1/2 its worth.
So, my recommendation is sit down with the phone and ring around, don't be afraid to ring back and ask if a "favourite" can do better when you have better quotes from others.