FRILLS OR NO FRILLS ?

I have a confirmed meeting in Singapore next Tuesday, and right now I am looking at flights. Although this will be a business trip, and as such the money isn't coming out of my pocket, I am still conscious of the costs because it will be coming out of my budget!
So, the choice is .. do I spend close to 10,000 baht on a 'full service' airline like Thai Airways flight, or do I spend a little under 5,000 baht on the 'no frills' carriers like Thai Air Asia or Tiger Airways? There is a middle option too - Swiss has a flight that is coming in at about 7,000 baht but the timing (late evening arrivals both ends) is not the best.
Thai Air Asia has mixed reviews on some of the passenger websites, whereas Tiger Airways has some very good feedback. I am leaning towards the latter - but I will let you know what I decide.