Hi = Ex British Airways type here; when we migrated back in 1973 our choice like yours' was between Perth and Brisbane we did the tour = the whole country on staff airline tickets two-years before we came here to live; (been in Perth since the age of Comets 64-y'o'-now) and never looked back, biggest differences between Perth and Brisbane seem to be that >
In summer Perth has low humidity due to overnight easterly winds that blow off the desert, or a screaming 10-20 knot sea breeze that cools the place down: typically by mid-day (earlier if very hot) so the place gets hot for only a few hours a day typically; hence the "fabric" of the houses on the coast seldom gets hot ; Inland suburbs can get seriously hot with slower wind speeds. I've lived in the same house at Scarborough (a beach suburb) the last 24 years and did a mini survey for a few years to see if I really needed Air-Conditioning; it worked out I needed it = 8-4-10-31days only: in the four years I bothered with my mini-survey) Scorcher the last year with unrelenting easterly winds'. We have great fine-sand beaches: some surf: not too big typically in the metro area' but can be "massive-massive" further south, (we also have "the southern hemispheres only warm water ocean current".= kinda important ?,) it's worth noting that Western Australia is about one third the size of either Europe or the USA. yet has only about two million people. (the National unemployment rate is about 4.2%, Perth is slightly lower) lots of fly in fly out with Mining companies paying great money (and you need great money to buy a house here now = like anywhere?). The definitive parameters for me have always been > "you must live where you recreate - you'll always travel to work???" Sunshine' cheap great food' and warmth' if you don't have to fight the climate and the sun says "Another beautiful day=enjoy" the consequence is of course that all the top-coats: disappear' and life is lived in lightweight casual/leisure clothing, just an utterly different lifestyle.
Far more than in the UK "very precisely where you live dictates much", so go slow on buying property, If you live somewhere humid; you'll get mozzies and bugs? in desert and semi-desert=Perth; you won't. Locally (***from the "ocean to the hills is 20 miles" of self-draining sand-dunes on which all houses are built, But still no-one leaves pots buckets etc' in the garden that might fill with water and allow mozzies to breed.***)
Brisbane is much more humid: and has mangrove swamps that go out to the mud-flats beyond which is the ocean which I've never actually seen from the city; no-one swims in the ocean close to Brisbane; but there are good beaches to the north and further south at the Gold-Coast = about 60 miles, which attract lots of tourists: domestic and flyins'' (Go-Google ) It will show you the mud-flats and the beaches: but not the mosquitoes???; Include dengue fever and malaria in your thinking particularly in the north of Queensland and to a lesser degree in the north of Western Australia, they say it will come as far south as as Sydney by 2020 ???) Climate change ? has resulted in both massive flooding and ongoing drought in different area of the bush on the east coast; with seemingly eternal cloud cover on the East-coast-beaches this last summer: Winter is the East-coasts sunniest weather; Coastal hotels and motels have had a really tough time of it this summer: as those guests that come: have little reason to stay, resulting in poor occupancy rates. It's (April-08-now) winter here now of course; but my suggestion would be to both look at >
www-realestate-com-au/ for an insight into housing styles and costs in different areas' and >
www-coastalwatch-com-au (sorry can't post URLs' yet) and open lots of windows on surf club cameras' so you can check "Is it sunny" and "Is anyone in the water" what's the water doing, is the beach blown out (windy)?
Remember also the issue of latitude; the "Brisbane to Sydney strip" would run from Casablanca to Rabat if it were transposed to the Atlantic coast. That Perth is on the same latitude as Jerusalem (and just as hot and dry). That relative to the poles: the "whole of the UK" is closer to the Pole than "any part of New-Zealand"; all of which is closer than "any part of Australia"; go-check ?
I hope this contributes something ) Every success with your decision.
= John; Scarborough WA.