This is the perfect place for long term stays. I stayed here for 2 weeks for a short internship at the UN Geneva. The room is very spacious with much storage place and large wardrobe. Also, the private balcony with a view of the mountains is super nice for eating your meals outside. A fully equipped kitchen and access to washing machine were much appreciated. Marlise is very tidy and clean and always available for any help or tips in the city. The apartment is very well separated for your own privacy. I was extremely confortable.
In terms of location: train station just at the end of street that takes you directly to the train station and other parts of France. Walkable to the old city and city center and Geneva lake. All possible to do in 15-20 minutes by foot. However, as I was working at the UN Palais des nations, the place was a bit further than I expected as it was an average 35-45 minute bus ride depending on traffic.
All in all, recommend Marlise place for your short or even long stays in Geneva!