My $0.02 for a good Thai restaurant on the East Coast, crazy as it may seem, is to check and see if they have a picture of the late Thai monarch Rama IX displayed prominently near the coat-check/hostess station/bar. I don't know what it is, but the Thai places who have his picture up are invariably better quality than the ones that don't.

But yeah, Thai food on the West Coast was reliably better.