My recent experience(s).
I tried calling to make a same day change on Friday that the QF website wouldn't allow me to change. After 30 minutes there was no answer so I had to hang up, cancel the flight and book a new ticket on the flight I wanted (otherwise I wouldn't have made it).
Then had to call again yesterday after QF cancelled a flight and moved me onto a later rather than earlier flight that wouldn't suit me (again, the website wouldn't allow me to change it myself). Apparently a 2 hour wait so I gave up and spent 5 minutes making a complaint about call times through the website.
Called back this morning to try and do what I couldn't get through for yesterday, the system said a wait of "less than 30mins" but I took the option for a call back which came through 40mins later and all sorted in less than 2 minutes.
That all sounds pretty consistent with what I've read here but the real interesting thing for me though was about 15 minutes after this I got another call from Qantas responding to my online complaint! I received a very insincere apology for my experience and was told "it wouldn't be changing anytime soon"! The honesty is refreshing but it does leave me scratching my head for reasons to keep booking Qantas!