This was a very cool experience. Gerhard left very clear instructions, with photos, for how to get into the bunker. He was quick to respond to questions. The bunker was very clean and spacious, with a really cool, fun aesthetic in terms of decoration, lighting, and design. (My daughter LOVED the multi-colored LED lights.) We didn't do any cooking, but it was nice to have a fridge and basics available.
The area itself is fine. There are a few supermarkets (I recommend Billa), though they seem to close early. Aside from a kebab/pizza place, there aren't a lot of restaurants around, though there's a whole street full of restaurants about two quick bus stops away. Lots of transportation options nearby, so you can get into central Vienna quickly and easily.
Checkout time was 10:00 AM, which is a bit early, but we managed. Overall this was a unique place to stay and it really added to our Vienna experience.