We flew with Thai Airways on both our outbound and return flight to LHR.
This is the second time I have flown to Thailand and previously we used Singapore Airlines.
We travelled Economy class and of course the main thing you want to look out for is the price of the airfair which Thai did offer very good rates for in which we could not complain about! Meanwhile after our experience with Singapore airlines was sooo good i wasn't sure what to expect with Thai.
To begin with comparing the two staff seemed much happier on Singapore Airlines. On Thai, staff looked very tired even before we departed! I am not sure if they had had a short turnaround however they all were yawning and their eyes looked bloodshot.
Being cabin crew you should always provide service with a smile. Out of all of the crew i think i saw one person smile. This reflects on their working conditions most definatley and how much they enjoy their job. Even so, people are on their holidays and dont want to be looking at people who have miserable faces.
Getting onto the food, on the outbound journey there was only one dish to choose from and they hadn't even gone round the whole aircraft. Clearly an issue with numbers when stocking the most popular dishes. On the return I had a fish with mashed potato. The fish was nice and flavoursome however the potato looked like yellow gelatin and was disgusting. There wasn't regular drink services and we had a 12 hour flight! i also remember crew coming round with a rubbish bag about once! in between food service. Being in Economy class is cramped enough anyway therefore having to sit with rubbish isn't nice.
I may be being picky however the difference in the details is what really sets airlines apart, even in Economy class. The cold towels were like thin makeup wipes. The ones on Singapore where like flannels and were of much better quality.
Overall, personally i would choose to pay the extra for such a long journey and fly with Singapore again as there wasn't anything that in my opinion Thai beat them on, sorry!