We walked by Thai Tony's on 7th between 15th and 16th on Sunday and thought that it looked very authentic - the cooks all seemed to be Thai and the space was very clean with an open kitchen (it's takeout/delivery only). So we decided to order our dinner from there - it is our new delivery favorite for Thai. The food was hot and fresh and the menu has all of the classics plus some more unusual dishes.
We had a crispy duck salad that was very tasty (if a little sweet for my taste), Tofu with bamboo shoots and a chicken dish. All three were fresh and had distinct flavors. I definitely put it above both Watana and Song (at least for delivery - the food was inedible the last couple of times we ordered from Song).
If you are looking for fresh, tasty, Thai in the South Slope, I would give it a shot:
447 7th Ave, Brooklyn 11215
At 15th St
447 7th Ave, Brooklyn, NY 11215