I probably had the best communication experience ever with Vera, Markus and their co-host Tina while staying at their place in Vienna. They are very responsive, helpful, easy-going and have a good sense of humor.
When it comes to the apartment itself then it is quite everything you can wish for - it is cozy, has an ideal location, literally everything what you could need is thought of - even the instructions on how to use the TV and WIFI are placed exactly where you would be standing/sitting while you realise you need them. The only downside I could think of is that the apartment was a little chilly, but since we were staying for only one night it did not bother us so much to even bring it up.
All in all, I would without a doubt recommend anyone to stay with Vera and Markus while staying in Vienna - it will exceed your expectations ;)