Restaurants don't have to try very hard to succeed in Irvine. The population boom pushed demand so high having less people in line for crappy foods is actually an advantage.
Nakorn Thai on GG Blvd across from the old people hospital next to perv shops is fairly good for OC. This place has mostly Vietnamese patrons.
nyc to oc said:
If you're willing to drive a little further, the best Thai place I've found hands down in OC is in Garden Grove--Jhumpa Thai. Came highly recommended by several Thai friends of mine. Definitely beats anything in/around Irvine, which is in general way watered down and too sweet.