This was one of the best places I've stayed, hands down. The apartment is super quiet, the internet is more than fast enough for conference calls and other business needs, spotlessly clean, super friendly hosts, and there's plenty of room to stretch out and relax. The shower had plenty of hot water, there are nice views from both sides of the apartment, and if you like graphic design and offset printing, there's some great stuff on the walls to enjoy as well.
It's not in the tourist heart of Vienna, but I was never more than 30 minutes away from anywhere I wanted to be - either walking through vineyards in Nußdorf or at the opera, there were plenty of options to get there. And Ottakring itself is - surprise! - a really cool neighborhood. You're surrounded by dozens of supermarkets, bakeries, restaurants, Heurige, and there's even a brewery just down the block - you will not go hungry or thirsty. Book this place - you definitely won't regret it (unless three flights of stairs aren't your cup of tea). I'd gladly stay there again if I ever get back to Vienna.