The airline with the best average rating is SilkAir with 7.7/10.
The average flight time is 1 hours and 55 minutes.More information
All three budget carriers (Air Asia, Jetstar, Scoot) flying this route had similar fares for this flight ($80 including 20KG bag one way).
On the other hand, Silkair was going around $180
My first ULCC experience with Scoot turned out to be okay, the seat pitch 28'' could be a problem for longer flights ie. Scoot's SIN-TNA which is 6 hour long.
There were no inflight service, no entertainment as expected.
I will fly Scoot again if they offer cheaper flights.