TPG is one of several Australian ISPs which has long been fond of offering "unlimited" plans. Of course "unlimited" doesn't always mean what you think it means.
The consumer watchdog has taken ISPs such as Optus to court in the past over so-called "unlimited" plans which actually throttled users back to slower speeds (256Kbps) once they hit a certain limit.
TPG's annual financial results includes details of a new "unlimited" NBN plan, reports Delimiter, which hasn't been officially launched and isn't available to customers yet. The fine print on the slide indicates that this unlimited deal applies to 12 megabit-per-second NBN connections, with no mention of faster 25, 50 and 100Mbps plans. We recommend you read the Delimiter article here.
It remains to be seen whether TPG would actually slow you down to less than 12Mbps once you hit a certain threshold.
As the Delimiter story points out, 12Mbps is much slower than the 24 Mbps theoretical maximum speeds of ADSL2+, so in theory you'd be better off on TPG's existing unlimited ADSL2+ plans. But the truth is that no-one gets 24Mbps via ADSL2+. Even if you're next door to your local telephone exchange you'll only hit 20Mbps over the copper phone lines on a good day.
As you get further from your exchange ADSL2+ speeds drop off faster than ADSL1 speeds, plus you're also at the mercy of the condition of the copper line. So there are plenty of users only squeezing less than 12Mbps from ADSL2+. If you're more than 3.5 kilometres from the exchange (as the copper runs, not as the crow flies) you'll be lucky to get 6Mbps via ADSL2+. Thankfully the NBN doesn't work this way and everyone connected to the fibre network should be on equal footing.
So whether or not you see the new TPG deals as good value really depends on the quality of your copper phone line, what you can currently squeeze out of ADSL2+ and whether you're content with an entry-level 12Mbps NBN plan rather than something faster.
The value of the TPG unlimited plan also depends on how attached you are to your traditional phone service. The $69.99 plan includes line rental, with unlimited calls to landlines across Australia and unlimited international calls to some countries including the US, UK and Canada.
It's worth noting that most ISPs offer the option of naked NBN if you don't require dial tone, so if you're ready to make the leap to Voice over IP then this TPG offer might not be the best deal for you.
[Update: This story has been corrected to remove a reference to TPG's current NBN plans. TPG does not currently offer NBN plans at time of writing. A reference to throttling has also been updated for clarity.]