My wife and I spent a week at Residence Martin in late October, 2014. We interacted mostly with Nicholas who met us when we arrived (literally, at the door). After showing us the room and communal facilities, he spent a good hour answering questions about Florence, what was best to see, how to get there, his favorite restaurants, etc, all of which was extremely useful (and accurate). During the week he always took time for us when we asked, although that was not often.
The room was clean and kept that way during the week. It had what we needed and was otherwise spare. The bed was comfortable.
The street noise was significant, but we managed to sleep well anyway and I was very amused by the daily cycle of the vendors setting up and tearing down their stands. Impressive and a hard way to make a living.
Nick and Veronica are nice people and they run a nice place.