This hotel is recommended by ETH Zurich to visitors that come to Zurich for workshops, training sessions or conferences. It's really convenient for this task, especially since the IFW building is literally next door (well, there's also a flight of stairs, since the whole building is on a hill). And it's only 5 minutes from Central, the city center. Oh, and rooms on the last (4th) floor have a beautiful view, as the hotel is on a hill overlooking downtown. But here's where the advantages of Hotel Astor end.
It has no ventilation what so ever (needless to say anything about air con, of course, there is none). That means it's sweltering in summer (and, even at night, nearly impossible to cool, as it's a superhuman task to create even a modicum of draft). While management has decided to provide all rooms with a fan, it's the absolute cheapest model, having absolutely no effect in making conditions livable. I've been to this hotel during a regular August day, when temperatures were about 30-31 C, and I've been told it can be far worse when heat strikes happen.
Additionally, the hotel is immensely noisy - there's a tram station just a few meters from the hotel, and the metal-on-metal brakes make fantastic noise. As they run way past 1 AM, every 2-3 minutes or so, falling asleep will be difficult unless you are a really deep sleeper. The walls and windows are paper thin you will (after a night or two) be able to tell apart the old and the new models of Zurich's tram fleet solely on noise. Even if you are not a public transport enthusiast! (note that if you are, this hotel might end your affection with trams and make you a car lover for life).
The combination of heat plus noise led to me sleeping a total of 12.5 hours over three nights. This, coupled with a demanding work schedule resulted in me having to take three days of vacation at home, after the conference was over, so I could catch back with my sleep.
And looking like a zombie for a workshop presentation was only mitigated by the fact that half of the audience (i.e. colleagues not from Zurich, also staying at Astor) was also unfortunate enough to stay at Astor.
Further, while I didn't care that much (I only wanted to get a decent night's sleep), the furnishings look surprisingly dated for a 3 star hotel. The reception closes at 20:00, making late arrivals awkward (you need to call a number provided on the door and wait).
Prices are decent for Zurich (translate to "a huge ripoff, extremely expensive" if you come from outside of Switzerland, but when you pay 6.5 euros for a bratwurst on the street...), but honestly, I would rather sleep in hostel dorm with 20 beds, if properly ventilated and if quiet, rather than return to Astor.