I've been eating at Yupha's since 2006, back when it was at the old location on Eliot.  I've kept coming back because the food is great quality and tasty.  Also service is friendly and ambience is nice and clean.  Can't ask for much more in a restaurant.  The reason it doesn't get 5 stars is because it's a wee bit pricier than other Thai restaurants for the amount of food you get.  I can usually finish all my food at this place, but at other Thai restaurants I pay less and take home leftovers.