This is a fine Persian restaurant. You have your standard kebob dishes but you also have the stews. Everything I've tried was good.
The noticeable difference with this restaurant is the guy behind the counter. He is so nice.
Prices are reasonable, though slightly higher than Super Khorak a few blocks north. The quality of the food is good. As usual for Persian meals, kebobs come with a ton of rice. This is not plain rice. For some reason, the rice at Persian places are delicious on their own even without additional condiments. Meal comes with free pop which is nice.
This restaurant is A-OK. I'd still prefer Super Khorak to this place partly because it's closer, and partly because SK is a little cheaper. SK also has greater selection of authentic Persian foods. But if I happened to be closer to Tah Deeg than SK, I'd go with Tah Deeg.