I have almost always had good luck with them. Occasionally things are not what I expected but for the price it is what I should have expected 😂 you get what you pay for. But I can get many things at a good price I can't get in Isaan.
Constantly varies. Use the websites mentioned above and also momondo.com. they show graphically the best times to fly. I just returned to ATL 2 weeks ago. It was not cheap. The high season is almost over so you should see some better prices. Also some airlines do not show up on aggregator sites so search direct with the airlines too. And Pattaya does not have an airport so you will fly into BKK and take a taxi.