I thought I posted a review, but apparently not! This is definitely a great place for lunch as well as a date / friends night out. Prices are a bit pricey, but the quality and quantity of food is decent. They are almost always packed during the busy times, so either go a bit earlier or a bit later for lunch. I wouldn't really recommend Pai for more than a party of 4 people as the tables aren't really suited for larger party sizes. For lunch, you can head over to the Pai market (head towards the washroom area) and you can have their dish of the day.
I have not had a bad dish here, but I would definitely recommend the Gaeng Massaman or the Kao Soi. But their pad thai is pretty good alongside of the Gang Kiaw Wan (it's curry...served in a coconut, which is a pretty popular dish).
Service: 4/5
Food: 5/5 (was...cooked enough, i think?)
Price: 4/5
Overall: 4.5 / 5 (Their dishes are always consistent and the kitchen is super efficient.)