Excellent environment, walking distance to Caltech, which is the nicest park around the area. Pasadena is a little, neat, clean town, comfortable and safe to walk outside even at night time. Ailin's place is typical airbnb one, not big but cozy and clean, and host welcomed us with a bowl of home-made Croissant and bread! If you are a hotel person, this may not the style for you; if you like to explore little town, especially Caltech, this is an ideal place to stay.