Literally a minute away from the Rennweg subway station, which is just one stop away from Wien Mitte, a major connector for all other U and S-bahn trains. Farhood's place is strategically located, and I would definitely return. If you're traveling to/from VIE, just hop on the S7 train, which stops here; it's a immensely cheaper than the CAT and only adds a few minutes onto your trip.
The room is clean, extremely spacious, and street-facing, so do expect some noise during the day. However, it all settles down by night, so it was no problem. A major highlight was the bathroom, which was sleek, white, and sparkling clean, and made me not want to leave. There's a BILLA (grocery store) a few steps away on the same block, and a DM (general purpose/pharmacy store) at the Rennweg station.
The only complaints I had were the sparse kitchen supplies (it had one pan, a carton of salt, TONS of plates and cutlery, but no pepper or oil). The bedroom curtain was also on the thin side, so if you like to sleep in or nap during the day, you'll run into some trouble. Otherwise, it's great for early risers and travelers looking to adjust their sleep schedules to the local timezone.
Communication-wise, Farhood was very responsive. I annoyed him with questions throughout my stay, and he always responded quickly. Thanks, Farhood!