I stayed at Ricardo's place for just over 2 months. It was a unique situation as it was during Lisbon's lockdown post winter holidays. So I didn't go out much and I was mostly using the space as an office for working. But it does mean I got to know the flat very well (better than Lisbon itself probably :P ).
The flat is pretty small but has a lot of charm. Very cute kitchen, lovely colours, decor and nice artwork on the walls. It's a good space to get in the zone and be creative, plus has that local vibe rather than the typical modern airbnb's with ikea style furniture. There are also church bells from Igreja de Santa Catarina that can be heard very clearly, which certainly adds to its character.
As for the facilities, the first thing I'd say is the internet was excellent - I was regularly getting 400 Mbps download and 100 Mbps upload speed there. So it was perfect for doing lots of video calls and streaming HD. Great dedicated desk space and a cute kitchen supporting it. Lots of sockets and neat little touches of using the small space well, and good provisions for the kitchen. The bed was very comfy, and the bedroom had a lot of space - I was able to fit my digital piano there too! My only complaint would be that there isn't much natural light - it's on the ground floor and it's surrounded by higher buildings etc, so be prepared for that.
Also should mention that Ricardo and the agency were very fast to reply and help me with my needs throughout my stay, plus check in was very fast. Would recommend them as nice, reliable and friendly hosts.