My fiancé and I stayed here for a weekend getaway. The location was really perfect for us -it's super central (just 5 mins from the train station) and we could walk everywhere. It's also clean and quiet at night. Communication was great and we could leave our bags there on the day that we checked out, which was convenient.
The apartment is great for a single person or a couple, but it is a studio, so make sure that you are comfortable with the person you are sharing with, otherwise going to the bathroom, etc. could be a problem.
We really recommend staying here and would do so again when returning to Lisbon.