There's a new Belong NBN promotion. From now until 15 December (extended to 31 Jan 2017), new sign-ups will get free speed boost for 3 months all the way up to 100/40Mbps (if you are fortunate enough to be on FTTP). Normally that's an $25/month option. Only up to 25/5 for FTTB & FTTN. Unmetered NBN is $65/month with 12 months contract.
Available in selected area only. Meanwhile my area (Sydney South-East) won't get NBN until 2018H2 and it's HFC only…
From what I've been hearing, if you don't suffer from congestion you'll get better speeds on hfc than on fttn.