I visited Vienna for a few days in September, 2011, and was based at the Cyrus hotel. My room was spotless and quite spacious. I ended up in a huge room with five (!) beds, but it was fine. It was however, the first place that I have ever stayed in which was 100% furnished from Ikea! It was kind of funny to see, but that’s OK, as I’m a fan of Ikea anyway, lol. The location, while not exactly in Central Vienna, was still good as the hotel was about a 2 min walk to the train station. As you do your search for hotels in Vienna you’ll find that the prices are quite high, unless you want to do some kind of backpacking place where you have to share a bath, which is not very nice at all. I think Cyrus is a good choice as it’s quite reasonable when compared to average Vienna hotel prices. There’s free internet (but only in the lobby area), and the people working there are quite helpful and nice.
I think it's worth a stay.
Hope this helped

The hotel is not in the city centre, but has very good connectivity by tram as well as U-Bahn. The room was spacious and clean, but I must admit a bit strange. There was a basin with an overhead cabinet in the middle of the room! The bathroom was very small and cramped and had no sink. It appeared as if the room originally served some other purpose and had been redesigned to make it into and extra guest room. However, overlooking this oddity, the room on the whole was clean and spacious. The bed was comfortable. The room had a set of windows, with pathetic curtains. Even though the hotel is on the main road, it was quiet.
The staff was friendly and helpful; we could leave our luggage after checking-out. They had basic, but an unlimited spread of breakfast; which for 3 euros is a steal. I would definitely recommend this hotel for a short stay in Wien.

As Vienna was one of the more expensive stops on our European tour we were quite price sensitive. However, as the Cyrus is near a U-Bahn (4 stops from centre) it was good value. The welcome was warm and we were allowed to check in at midday. The room was ok, though we were given 2 single beds and it was outrageously hot in there.
Breakfast was included but so basic on day 1 that we didn't bother day 2.

The hotel is not half as bad as some of the reviews make it out to be.
The location is excellent, only 5 minutes to the centre by underground.
I don't know why some said the hotel was dirty, we found it perfectly clean.
Continental breakfast is basic, but there's cheese, bread, ham, different varieties of jam, pate, chocolate paste, honey, etc Orange juice, tea, coffee, hot chocolate. Enough to have a good breakfast before going out in the morning.
Wifi only works in the reception area, and there are two computers there which people can use if they didn't bring their laptop along.
The man at the reception was helpful, when we asked for some some spoons and knives to take to the room he gave them to us and let us keep them till the end of our stay, he gave us an iron when we needed it, and when we arrived and found the little table lamp not working, he went up and fixed it immediately.
The room was cleaned and towels changed every day of our four days there, except one (I think). It's true that in the bathroom there's no place to hang your towels and you have to reach outside to grab them from the rail. But I actually liked the fact that the basin was not in the cubicle with the toilet and shower, but separately, near the entrance to the room. It meant we didn't have to wash fruit and cutlery in the bathroom.
I do not know why some people are complaining about noise - the windows are soundproof, so when they were closed, you could not hear a thing outside. Even when we were open, there really wasn't much noise.
I would not advise you to get a Vienna card, as it is really not worth it. Despite what I read online prior to coming, you do not get a discount on the train from the airport. And the museum discounts are totally negligible, ex. you pay 11 instead of 12 eur. Especially if you're under 18, like me, or have a child under 18 with you, the Vienna card is so not worth it because in many museums children under 18 either get 50-70% discounts, or even go in for free.
One of the reviews said that the metro stations are not manned and many people go without tickets. While the latter seems true, I would not advise it, as during our 5 days of stay, our tickets were checked three times.