I rely a lot on the comments of other users before I book. Therefore I will write what worked and what did not.
Plus
The Loft is absolutely gorgeous. Spacious, full of light and on the river itself. The host has equipped it really well - very good quality and very tastefully done. An artist's dream!
Minus
The host takes a bit long to respond. We had to delay our entry since I did not hear in time from him about the check in time. Our previous host in the city had graciously allowed us to exit late therefore it was not an issue for us, but had we been travelling into Berlin from overseas this could have been a big problem.
There is construction all day from 7 am to 7 pm just across the river on the East side. The distance is just 100 m, so you wake up to drills and an afternoon nap is possible only with the windows shut. May be good in winter, but in the summer, this is definitely a problem.
The neighbourhood is not that good. It feels unsafe to walk alone at night.