Being a big fan of burritos I was very pleased to find this place close to my home. I have eaten there many times now and have also tried the delivery service. The place is clean, modern and cheerful inside, with seating for maybe 11 maximum. As others have mentioned the frontage is very low key and easy to miss from the street.
As well as the food they have a small fridge with Mexican sodas and beer.
The veggie fajita is a consistently good favourite and is served with a small complimentary side of tortilla chips when eating in. The steak or carnitas versions are also good but sometimes can be very wet (as in liquid dripping out of the bottom while eating). Regardless, I'd be happy to have them any time.
As the previous owner of a small hospitality business (unrelated) I am always happy to recommend a place which is doing it well and Tomatillo definitely are. The food is great and you can tell they are well organized. No better comfort food on a wet grey Amsterdam day :)