Yusef is an amazing host. Besides just being a great guy, check in was easy, the apartment was clean, the kitchen was well stocked. He also speaks both English and German and is an architecture student at the university.
The room was really big and there was more than enough space for my boyfriend and I, our baby, the stroller, and all our luggage. It's clear that Yusef put a lot of thought into the apartment, because it has just about everything you could possibly want: maps of Vienna, a hair dryer, coffee, and yes (despite old reviews) wi-fi :) we were especially grateful there was baby shampoo, which we forgot to bring, and a washing machine. The best way for us (because we had a lot of stuff) to get into the city center was to take the train just a five minute walk from the apartment to Oper. You can also walk 15 minutes to either of two train stations or 25 minutes to the city center.
At the end of our week log stay Yusef also left us some small gifts which we are still enjoying :) seriously the best host ever!