I've been looking for pad gra prow (basil chicken on rice with a fried egg) ever since I had it from a street stand in Thailand. This is the first place that I've been able to find it in Toronto and it is just as good and authentic as I remember. I highly recommend this dish.
Pad thai - Pai's version of pad thai not a favourite of mine. I think it lacks the tangy tamarind that I prefer (although maybe it's more authentic this way)
Green curry - good curry with the added bonus of being served in a coconut. Be sure to scrape out and eat the coconut meat when you're done.
While this place is often packed (my friend and I went at around 6PM and we still had to wait about 10min for seats at the bar), the staff are friendly and take the time to make good recommendations.
Having been to local favourites such as Khao San Road, Sukhothai and Salad Kind as well, I have to say that Pai wins as my favourite Thai restaurant in Toronto.