I only managed to go to this place once and the noodle soup I had was really good. It had much more veggies in it than at most places and different mock meats. One soup costes 30 Baht. It has a really authentic street stall feeling, which is really difficult to find if you're veggie. I'm always jealous of meat eaters who can just sit down at any random street stall and get really tasty food wherever they are in Thailand.
If you're inside the India Emporium, you can walk straight out the back door and you'll run straight into the stalls. There is also a veggie Indian stall selling samosas, pakoras and aloo tikkis on the left side of the India emporium and a veg Indian and veg Thai stall in the food court of the emporium (next to other Indian stuff, which is already very veg-friendly).
Cons: maybe too hectic for some, not for me