Overall I recommend Maria's place if you're looking for a simple place to sleep near Santa Justa station. There are 4 or so bedrooms that seem to be airbnb rooms also, so it doesn't really feel like you're staying in someone's house, but more of a collective space. It's good if you want to be on your own. The only problem with this is that the rooms don't have locks. The room was clean, but very hot with only a small fan. She provided towels for each guest which was really nice. The bathroom and living space was always kept very clean, though sometimes the hot water wasn't working in the shower properly (hot-cold-hot again). The kitchen has a fridge and stove but we were told we couldn't cook dinner, which for most people wouldn't be a problem but we were staying for a week and wanted to make dinner sometimes, which ended up not being possible. You can make breakfast in the morning however.
Maria was very helpful and all the check-in instructions were clear. She was always available whenever I had questions. The communication once we arrived was great, and I would recommend her as a host.