Just tried Sutra with my wife based on the fairly positive review in the Observer. I must that that we will never be going back. The food was terrible, the service was worse (we observed Indian customers getting prompt and friendly service while anglo customers, us included, were given rude and bare bones service), and the prices too high for what you get.
Food: I got the mahi mahi in a green curry sauce. The sauce was alright, but I could barely taste the 2 medium-sized pieces of fish (which were slightly overcooked). The wife got the baby eggplant. The actual dish was only 3 very tiny baby eggplants swimming in a giant bowl of green sauce. The eggplants were rock hard with little flavor and the green sauce was terrible. She had 3 bites and had to stop. The entrees also came with a small salad which was also terrible due to the awful salad dressing.
Service: We went in for lunch at 12:30 on a Saturday. The only server we assume was the owner since he was dressed as he was either coming from or headed to a gym to work out (a ratty shirt, gym shorts, and tennis shoes). He was rude, did not discuss the menu or ask if we had any questions, and generally very surly. There was only 2 other tables with customers. After we received our entrees (without any sides of rice or naan) he walked away and ignored us. We started eating and I observed him getting a rag to go bus the table of the people who had just left. I actually had to stop him and request a side of rice. He did return with the rice and the naan that were supposed to come with the meal.
While our service was terrible, the worst part was watching 2 tables of Indian people come in while we were sitting there. They both received warm and friendly service, were chatted up about the menu, and their food was served promptly (and also served with the rice and naan).