The flat was clean, the location is an easy walking distance to the DLR line, and I felt generally safe in the building, so not too bad of an experience overall. It also had a really nice little kitchen, with all the key appliances and dishes you'd need.
That being said, there were a few surprises with the apartment - like it not being the one pictured in the listing (was apt 4 - you can see the 3 on the door of some of the posted pics), the bathroom only being accessible through the bedroom, the back of the toilet being duct-taped to hold together, and the aggressive all-caps rules on the back of the door. Also in the surprise category - the flat has a washing machine! That came in really handy. So, pros and cons with the unexpected things.
Biggest complaint though is that it was also a very stressful experience trying to get check in info from the host. Although I booked over 4 months in advance, and messaged multiple times in the week leading up to my trip, I wasn't able to get info about how to check in until right before I boarded my plane to travel half way around the world. I was very concerned that I wouldn't have a place to stay once I got off that 12 hour flight. In the end it worked out, but the host needs to work on better communication.