I just swithced to iinet.
I pay around $50 a month for the same net usage as I had with telstra for $90.
I pay around the same for line rental & have a voip pack included for $20 extra. My voip includes all national calls for free. Mobiles are 30c a minute. Not sure about call blocking or anything though...don't have teens yet, lol.
Only problem is that I need to pick a thing up for my voip that I keep forgetting, so not sure how it works yet.
I can call land lines from it & have a seperate number for people to call me on it (not sure if its cheaper for them or not though).