It's funny how we spend thousands on restaurant bills for minuscule servings,while some street side stalls serve scrumptious food for 20Rs.
If we look for a stall in clean surroundings, hygienic looking food and cooks,there is no harm in trying. For eg. I tried this thali in Kalkaji for 20Rs. Tastiest kadhi and Chole ever. Also the cook was so happy to hear his food is amazing.
There is nothing 'low class' about street food,provided we are ready to accept it and not associate food habits to social status.