I apologize for not mentioning that. As someone who lives in Berlin I'm used to calling a trip from 30 minutes "fast", so I didn't think of it. My bad.
Before you book a room in one of these Motels make sure that the travelling route to the Estrel is comfortable for you, especially if you need to carry stuff to or from the convention. The average public transport travel time from Point A to Point B in Berlin is between 30-60 minutes, depending on the exact location and the kind of vehicle available (Underground is much faster but maybe a few minutes further away than the Bus stop etc.) In my experience you usually have to change trains 0-2 times per route though this varies of course.
On every Motel One page is a tab named "Location & surrounding area". On the left side you can find the stations and bus stops near the hotel. Click on "Berlin public transportation" to get to this official journey planner:
http://www.bvg.de/en and check if the route suits you. Also check it for a travel time at 2 am to make sure you aren't stuck at the Estrel at night.
If you go by car use the address on the front page of the Motel and your favorite navigation system.