Very good experience overall. I was greeted by Liliana, very nice and friendly lady. She provided me with a map with nearby tourist places. She even drew me a route. The place was nice and clean and the location is very convenient. Many tourist places like Colosseum, Forum, Palatine, Pantheon, etc are within walking distance. The Vatican is probably a bit too far to walk because by the time you will reach there you will be tired already, there is a lot of walking involved if you want to see places in the vatican itself so I would recommend taking the metro for the Vatican. The metro station is less than 5 minutes walk which can take you to The Vatican. There are plenty of places to eat within walking distance open till late night.
I found it a little bit difficult to find the building entrance. I was walking up and down the street trying to find the entrance. I could not find the building number I was given written anywhere. After a lot of effort I found a handwritten small label on an intercom button that says Maria's guesthouse which kind of matched with the address). I was not told by the host that it was called Maria's guesthouse. It might be useful to have clear instructions for the guests. But once I had found the place and checked-in it was all good.
Overall, a very positive experience, I would give it 5 golden stars for nice place, lovely host and a very convenient location.
Tips for future travellers:
1. The place is called "Maria's guesthouse". The building number on the outside says 15 (the address you will have been given will say 16, look for 15). The entrance is the one door next to the laundry. On the intercom buttons next to the door look for a label that says "Maria's guesthouse". Inside the front main door there 2 doors both are locked, go to the one of the left and again look for the intercom button that says "Maria's guesthouse". Go to 4th floor and you should be OK from there.
2. Make sure you have cash with you to pay for the tourist tax which is euro 3.5 per tourist per day. Make sure you have change.
3. Colosseum, Forum and Palatine are about 15 minutes walk. There is so much to see in these places alone that it will take the best part of the day (if you are interested in history).
4. Although Liliana drew me a route (which I am sure was good) but I followed my own and for me it worked great. Liliana suggested walking to Colossuem and then walking up all the way up to Trevi fountain. I did something different. I took the Metro and went straight to The Vatican and then backtracked my way from St. Peters -> Castel sant angelo -> Pantheon -> Trevi and back to the hotel, all on foot, very enjoyable walk and took the best part of the day.