Quality is what you're paying for when you come to Khao San Road. After only waiting for 20 minutes to get a table (come early, reservations are not taken), my girlfriend and I were seated at the bar.
The bartender quickly acknowledged us and served some water. After a long musing, we went with the shrimp appetizer to start. Overall on the smaller portion but plenty of flavour. Would recommend and get again.
On to the mains - we both ordered the three flavours pad thai (one veggie and one chicken). The food came out in a reasonable amount of time despite it being a full house. Both dishes were fantastic. Whatever formula they have is spot on - you can taste the quality with each bite and you know that the food isn't topped with a lazy man's tamarind sauce. The chicken was plentiful and same with the veggies on my girlfriend's plate.
Nothing else to really say other than what has been said below. Happy eating!