I had read the reviews and decided to book with Xiamen airlines regardless. The flight was $320 AUD with the next cheapest airline charging over $900 for the same flight.
I was pleasantly surprised. The staff were very friendly and genuinely helpful. Whilst not fluent in English they were able to communicate enough to get the job done.
The plane may have been old , but it was still clean and most importantly functional. The pitch being at the higher end for economy flights, particularly on budget carriers.
The food service commenced very early and there was adequate food. Whilst not a gourmet experience, the food was adequate. They did serve crackers in lieu of peanuts, which were really tasty. On the second flight they served mixed nuts and dried fruit, which was also a nice touch. I'm unsure if you can help yourself to snacks and drinks, like you can on Qantas as the food served was sufficient.
I had an 8 hour layover in Xiamen, whilst not ideal, there is filtered water stations, charging ports and reasonably comfortable chairs. The staff in the shops there speak very limited English so Google translate was a great help. If you want to buy anything in China, you should consider downloading the wechat pay app, as it is accepted pretty much everywhere in China.
For a third of the cost, I'd fly Xiamen every single time.