I've got both NBN and Netflix and it takes approx 3 - 5 secs to load any Netflix show/movie.
When I speed test my NBN connection it averages about 97 mb per sec...
My download spees peaks around 15 - 18 mb per sec
I'm with iinet and pay $13 per month for Netflix and Netflix is not included in my monthly data allowance.
I pay about $60 per month for top iinet NBN
I also have the house completely networked (4 panels, 1 pc 3 laptops, 3 tablets, 3 phones) via Hills Hub and a NAS.
Here's my wireless speed from furthest wifi point from router in upstairs back room. testes on my Samsung Note 4