I stayed at Johanna's place for 5 nights to attend an event at the Essen Messe. Johanna herself was nothing short of fantastic; she helped me with several transportation issues and took me on a walk around the neighborhood so I could become familiar with the area. Her English is excellent, and she is a very intelligent and thoughtful person. She was only in Essen for one day during the time of my stay, but she was easy to contact. She is very well traveled herself, and has even worked in a commercial hotel so she can anticipate the needs of her guests.
Her place was clean, spacious, and I felt right at home with everything needed provided for me (when I booked her place Johanna didn't have "essentials" checked on her profile but she did had towels, soaps, napkins, and other basics all ready in the apartment). It was within a nice, leisurely 10-minute walk to the Messe, and even closer to a main commercial streets with dozens of shops and restaurants. U-bahn and tram access is also within 2-4 blocks of walking. There is a nice deck area for enjoying the nicer weather, and WiFi was provided.
There are only 2 things that might cause you to hesitate to book Johanna's place (and neither were an issue for me): 1-Johanna lives on the top floor of her building without an elevator, so if a couple flights of stairs are a problem, I wouldn't recommend this place. 2-the bathroom's ceiling is angled and very short, which basically prevents normal stand-up showers (especially for taller people). However, Johanna's bathroom is very well equipped for bath taking so this is not a real problem. So, as long as you can handle stairs and aren't too terribly tall, this apartment is an A+.
I've only stayed at 3 places using AirBnB during my travels thus far, but Anna's has been the nicest, most comfortable for me. I HIGHLY recommend!