The first thing you should know if you want to stay at Mabel's place is that it is not walking distance from the main tourist attractions in Medellin. However, you have taxis available 24/7 that bring you either to any place (price according to the place) you want or to the metro station Ayurà, price for metro station, for about 2$USD (5500$ colombian pesos).
I would really recommend, if you are looking for cheap food, a pizza truck in front of the main entrance that sells amazing pizzas for about 8$USD which three people eat from. It was really good.
Mabel was always making sure everything was fine with us while there, via email since she wasn't there during our stay. Overall amazing host and clean apartment.
We had some issues with the water heater but nothing major, we had to move the batteries around and it would work afterwards.
There is also satellite tv, with lots of different kinds of shows, which was helpful since we were traveling with small children.
Overall, I would definitely recommend this place if you are looking for a fair price in Medellin and a great apartment.