Having just changed to NBN from ADSL, one thing seems abundantly clear - your ISP more than ever is simply a re-seller.
In the past, you might have been better off with Internode, iiNet, Westnet, etc - companies who tried to provide better service and better backhaul, who had to varying degrees their own DSLAM's in exchanges, tech support until late at night, and the ability to actually DO meaningful tech support beyond "have you tried another modem" (because we all have 3) and "how long is your cable" .
Now it seems very different - ISP's appear to be completely at the mercy of NBNco for any meaningful troubleshooting - well, it would be meaningful if NBNCo could back it up with something called meaningful troubleshooting - and accordingly ISP's are ratcheting back service levels, probably because NBNCo doesn't provide anything meaningful coupled with the good ISP's being snapped up by the churning giants like TPG. For example, eons ago you could get fairly good tech support from Internode until quite late at night, and at times on weekends (I don't recall specifics). Until fairly recently (this year I believe) you could get better than level 1/frontline support until 2000 CST. Now its 1800 or 1830 CST? and completely hamstrung by the NBNCo service filter.
On top of that - people experiencing "get NBN now" and finding they can't get it. Big delays in service installation, and a huge failure rate on initial cut-over, and sometimes up to 3 or 4 appointments before the service is running, each time being told your "appointment" is a 4 hour window (that's a time-frame, not an appointment), that someone over 18 years old needs to be present, and seemingly a zero percent chance of anyone even making contact during the allotted time-frame, let alone actually showing up. In our case, 3 weeks of no internet after the so-called cut-over, 4 appointments where no contact was made and nobody attended the premises (even though on one occasion they claim they did attend, gain access, and test the wall socket - apparently without our knowledge!).
Add to that the installers having hand-written install sheets and minimal English skills (as reported by a friend who stopped by a node, I've never even seen them) - what could go wrong? Admittedly I am in regional Australia, but a sizable town.
Lessons I feel we have learnt:
* Don't expect your cut-over to be scheduled in a timely manner
* Don't expect the "cut" part of your cut-over to be immediately followed by the "over" part of your cut-over. You could see a gap of "weeks"
* Don't expect any kind of testing of the new service, quality control, etc.
* Don't expect to ever see an NBNCo contractor
* Don't expect to get meaningful responses back from your ISP (they are almost certainly as frustrated as you)
* Don't expect NBNCo to prioritise fixing their mistakes, they just make a fresh appointment and you'll need more time off work to be there when they don't show up.
This is of course all anecdotal - but of the dozen or more cut-overs I'm aware of two (2) went without a hitch.
The other question raised is what value does the ISP bring to the equation now? I know they provide the back-haul from the NBN interconnect and upstream/peering/etc, email and some local mirror/etc, but it really seems like the reason to go anything but "cheap and nasty" has all but gone. Sadly ...