I actually stayed 3rd time at Mary's place and this time this was a new location. It was clean, bright and comfortable place right near the DLR station. Mary provided (as usual) detailed instructions of how to get to the place, and always replied within 30 min if I had any questions. In the place there were complimentary adapters, tea, coffee, travel guides, printer and high-speed wifi.
I really recommend this place if you need to have a quiet place from which you quickly get to Canary Wharf by DLR or by foot.