In my opinion, the 5 star rating is heavily influenced by the food & wine served during the flight. For example Singapore Airline serves caviar & Dom Perignon in the business class, whereas Emirates don’t. I have used both the airlines on the Dubai –Singapore route ; Emirates wins in general comfort.
Comfort, food & treatment of the passengers are no doubt important but it is still secondary to the safety. Air travel is supposedly the safest way to travel very long distances; nevertheless airliners do go down fairly often. It reminds one about the fragility of human life and makes one think twice about stepping into the plane.
Most airline crashes are either due to the pilot error or poor aircraft maintenance. Nothing much can be done about the pilot; one hopes that most airlines would have properly whetted their flying staff before they are allowed into the cockpit. However, aircraft maintenance & airworthiness is directly related to the age of the aircraft & diligence of the airline engineering staff; here one has a choice.
Even though I have twice travelled in a private jet accompanying my boss; I admit that I did not make the grade for the first class entitlement and except on rare occasions when no other seat was available, I travel business class. I did not find a lot of difference among various airlines in food & comfort level especially when travelling in a wide bodied jet.
Regarding safety, I have one simple rule; travel on the airline with the newest planes. For most of my travel routes, the two UAE airlines Emirates & the Etihad have the most modern fleet and these are my favourite airlines.
I am surprised that neither of the two is in the list.