Etihad seems to be backed up with loads of money. Appears to expanding fast, money is good and tax free. However everything & everyone in the ME is short fused. It could all change with the blink of an eye, or you could work & retire with a nice pile in your nest! It`s anyones guess which way it will go.
SIA on the other hand is here for the long run. A well run company and stable as the best in the world. Singapore as a city itself has plenty to offer, heaven, compared to any place in the ME. Locals are much more decent than the Arabs. Everything is done with efficiency, unlike the ME where it`s total chaos. What will bite your pouch in Singapore will be the tax & everything is rather expensive.