The Iris Congress Hotel is about 20-30 min. outside of the city center by tram. The tram stop is Slavia. This is a new hotel that is attached to a soccer/football stadium, across the street from a shopping mall. I stayed for about 10 days.
I was slightly concerned about the noise level during a game, but the games were in the early evening and never seemed to be a problem for me or any of my attendees. In fact one of them had one of the only rooms overlooking the stadium (429) and thoroughly enjoyed it.
The food at the hotel was great. The service was okay. The hotel bar is only open until 10pm each night and this was a problem for my attendees as there really wasn't any other bars or restaurants in the area to go to. Many went to the 24 hour Tesco in the mall to get alcohol and hang out in the lobby.
There is free wi-fi in the lobby which everyone liked. Also, you can get free ethernet in the hotel rooms if you unplug the cable from your phone and put in the computer.
The rooms were clean when I got there, but I can't say that the daily cleaning service did much more than make my bed and take out the trash.
The front desk personnel varied by the day---some were extremely friendly and some gave you bored looks when you asked for help, however they all provided the answers I was looking for.
The tram was very easy to use and only about 1 block from the hotel. Be ready to spend a lot of time on the tram, as I've said before, there's not much to do in this area.
Overall the hotel is a good value for the money (US$45/night) it's just a bit of a distance to the sightseeing areas.
One further note for business people, they do not have a business center, though they are marketed as a "congress hotel" and there is no place near the hotel to make copies. The staff accommodated me by having me email the reception and having them print things on their fax machine. This was a slow process and didn't lend itself to the usual amounts of mass copies I need for an event.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC