No, they are terrible, for thee old ADSL they are pretty good but all of those should be much higher. I'd complain and if that dosen't work threaten them with going to the Ombudsman, that sometimes helps. When nothing happens never vote Liberal ever agian, they lie as much as Telcos do and this NBN is a joke, it costs more money than the one Labour was going to build, isn't done yet and is woefully slow - aaaaand expensive. I have a mate in NZ who pays $30 a month for 98mb/s.
Mine started off at 25mb/s down, 10 down and ping is 48, it's now half that and they say it's due to peak traffic.
You are welcome, I recomend changing to Iprimus or IInet, both Optus and Telstra are over priced and terrible at customer serivice. If you already have a contract insistist that they meet their obligation of delivering better speed than at least ADSL2+ which is cheapr and the speed you are getting now.
I've replied back to your original thread on this topic here → https://yescrowd.optus.com.au/t5/NBN/NBN-Broadband/m-p/345866#M9855. I've asked that you send through your details via PM. We're more than happy to discuss some options with you.