I stayed at Martin's apartment for two nights with my husband and 3 year old as part of visit to Portugal. The apartment is beautifully furnished, comfortable, and in a central location in Lisbon close to transportation and restaurants. Having the elevator was very convenient (though for anyone with mobility restrictions, be aware that it starts on the floor above the ground floor!). Check in process was great - Martin's colleague Marfalda was flexible about time and very kind to meet us at the apartment (and wait when we were running late!), explain all the quirks of the old elevator, give us tips about local restaurants, provide a generous welcome basket with wine and pastel de nata, and even help us with bags when our daughter decided she was scared of the elevator and wouldn't go in. The apartment was cool, the beds were comfortable, the bathroom off the master bedroom is spacious, and the windows do a great job blocking out street noise when closed. Plus it's a beautiful space to spend time in! My only complaints were that the apartment got a lot of noise at times from other guests going up and down the stairwell, and that the main bedroom has two single beds rather than one large bed, but neither of these were major issues for us. The location is also fabulous in a flat part of Lisbon near multiple pedestrian streets with lots of restaurants and shops as well as various bus and subway lines.
One minor note - the glass water bottle provided as part of the welcome basket is reusable and needs to be kept!! I had missed this when we were checking in and it wasn't noted in any of the written apartment instructions, so I put it in the recycling when trying to follow the explicit instructions to taking out all the trash and recycling before leaving the apartment, only to be asked where it was and then charged for it after we left. It was a nominal charge that I was ok with paying, but I was somewhat taken aback by the hosts' attitude towards an honest mistake when we'd otherwise been very careful (and hopefully successful!) about following all the house rules and leaving everything just as we'd found it. Not a big deal, but wanted to mention so others don't make the same mistake we did.
All in all, a fantastic apartment that I would highly recommend to any other travelers!