I've had a pretty good experience with QR's Privilege Club.
The joining bonus, two return economy flights from Oz to France and a bit of duty free got me enough Avios for an award ticket from Australia to Jordan via Doha. It was easy to find, plenty of availability.
1 1/4 return flights to Toulouse in France (one from Adelaide, one from Sydney) got me to Silver membership status - I hadn't paid any attention and wasn't expecting it but the digital membership card in my Apple Wallet updated instantly and notified me as soon as I arrived in Doha, and I was able to use the Silver lounge there. Silver is equivalent to OneWorld Ruby and doesn't give you anything on OneWorld partner airlines or lounge access anywhere else, but if going through Doha which almost all QR flights do it's handy, and it gives you priority chicken and boarding and an extra 15kg of luggage.
Worst aspect of QR is the extortionate prices for seat selection.
Unfortunately for me they stopped flying from Doha to Toulouse last year otherwise they'd be my first choice.