How is the internet speed like in Truganina?

Depends on which NBN technology that connect to your house. Where I lived (The gateway) I had FTTP (Fibre) with Telstra - the speed was consistent,stable with excellent download speed.

The internet is good NBN fibre to the curb (fttc)

I have got ADSL 2+ without issues, you can always do a serviceability check on the Telstra site to see whether you would be able to get the service. Some of the newer estates already have NBN.

Some estate near Truganina can get NBN Fibre and can get up to 100mbps for their broadband speed. You can check NBNCo website for your exact location and validate if you are covered by NBN network.

Yes it is atrocious, I had to fight to get ADSL 1