If you're looking for an affordable, convenient and clean rental with comparable space to choosing an entire home/flat, Mary's flat is an excellent choice.
However, unlike an entire home/flat you're guaranteed an extremely welcoming host - offering insight and suggestions into the area and more than willing to converse.
Regarding the area, it's an ideal location with Old Street just around the corner, providing great links to some popular areas like London Bridge; It was very little hassle for me to travel towards Canary Wharf!