The best replacement for optus is telstra.

The best alternatives to optus are rated as following:
★★★★★  telstra
★★★★  vodafone
★★  telstra broadband
★★  telstra cable
★★  tpg
★★  vodafone coverage
★★  virgin
★★  telstra 4g
★  iinet
★  telstra coverage
★  telstra mobile
★  telstra prepaid
  telstra internet
  virgin mobile
  virgin coverage
  telstra iphone
  telstra mobile coverage
  foxtel
  telstra better
  bigpond
  nrl afl and telstra
  telstra mobile broadband

Your alternative for optus is not listed? Suggest!
Speaking about optus, one probably shouldn't forget about foxtel.

Other search terms related to optus and their ratings are:
★★★★★ foxtel
★★ tpg
You have in mind a companion for optus and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of optus in all years. Click on graph for more.
optus
telstra
vodafone