I loved this place. It is as described in the listing - good wifi, AC and heater, kitchen (including stove and oven in addition to microwave and fridge), bed, sofa, tables + chairs, nice bathroom and shower, and towels and sheets. The patio outside also has a table and chairs, and is a nice place to work. Washer and dryer are shared with the main house, and free.
The location is fantastic. There's a convenience store a few blocks away, so that basic necessities can be bought without needing to drive. JPL is within walking distance, and there is also a bus stop nearby, from which you can take the 267 straight to downtown Pasadena, Memorial Park metro station, and Caltech/PCC (or if you have a car the drive to Caltech is about 20 mins). Several mountain trails begin within a five minute walk from the apartment, so that hiking can be a daily after-work activity instead of a weekend excursion. For runners, besides the hiking trails, there's a nice path which you can take south along the Arroyo to the Rose Bowl loop.
When I had any questions, Chris answered and handled things very fast. On the whole, I had a great experience and would definitely stay here again.