Hi Sue.

In our case we have both, wife has optus works well at home and have better plan incl nbn,  keep my mobile with telstra for travelling have a modified S4 with external antenna on roof of tug signal most places mind you some places there are none.

BT

Telstra, or Boost which is the only other company that uses their full coverage system, has by far the best coverage.   But depending on where you are travelling you may not find it an issue.     In WA Optus coverage is basically limited to the south west.   Take a look at the coverage maps from https://www.telcoantennas.com.au/site/coverage-checker-all-australian-networks  to see if the Optus coverage will work for you.    It wouldn't be any use for us for much of our travels so we have stayed with Telstra

G'day Sue

Like others here we use both systems

we are NSW home based, and do 75% of our touring thru eastern Oz

We have Optus as their rates offer is more suited to us that Telstra
We also have a Telstra fone with the $140 x 12 months pre-paid deal

We find that wherever we pull up at night -
Optus has about 90% coverage of those places
Telstra has about 90% coverage of those places
but - often one gets a signal and the other does not get a signal ... ie: carrier priorities etc

thru the day as one goes thru towns, it's a 50/50 bet as to who has coverage

It is a different matter west of Longreach and across to Broome
Telstra has 90% coverage again
Optus has 50% coverage - more of the big towns

However, the Telstra coverage disappears once you've hit the 100km/h speedo sign, not to be seen until you meet the next 60 km/h sign


Phil

I've got the $50 a month 8GB unlimited phone and SMS plan. No problems with coverage. I only travel along the coast of QLD and NSW though.

We just did a 9 month trip around Australia using Telstra (not a fan) mostly good reception and in many places where you wouldn't think there would be service.
We frequently noticed other people in frustration trying to get a signal. If we asked them often the answer was they were using Optus or Virgin.
We reckon the best Telstra deal is the $140 X 12 months deal.

Check out the Aldi sim card. Very competitive and uses the Telstra system. 3 of my family use them with no problems whatsoever. Prepaid and have the choice to change your usage month by month if you wish.

Having just returned from doing the great lap,DO NOT rely on Optus over in the west.Virtually no coverage.We travel with two phones one with Optus and the other Telstra.Even so,often on the west coast,we have no service.Same goes for dongles for laptop.One of each if you rely on the internet.

We were with Virgin (run through Optus) until we moved to Imbil - now we HAVE to be with Telstra, otherwise we have no coverage. At Tin Can Bay, Virgin was iffy, and non-existent at Rainbow. WIth Telstra, he is on the long-life plan ($100 for use over 12 months), and I am on - can't remember he name, $700 calls/texts to *standard* Telstra numbers & 1.3G data a month for $30. Both pre-paid.