I stayed with Merlin and Roberto for about 2 weeks, and it was a very pleasant stay :D Both were very friendly, kind and comfortable to stay with. Whenever I had any question, they quickly replied me and helped me (either through email or face to face).
The room with stylish interior was very clean, and there was a number of DVDs to enjoy!! They prepared many amenities, including even lovely bath salt, and could see their kind efforts in many points to make my stay as comfortable as they could :)
The location was pretty good. It was easy to access the DLR station (5-10mins walk), and there is a bus stop for Stratford just in front of the building (about 10mins to Stratford). I highly recommend their lovely flat to stay!