The IC prague is nice... I haven't been to Vienna...
The IC Prague is in a fantastic location, the service is good but some of the rooms are a little run down.
The lounge is good for the price. Reasonable food options but I don't like the layout.
I had a massage there and it was pretty good. The gym is laaarge for an inner-city hotel gym. and they do lots of classes.
Overall I do like the IC Prague, it is very affordable.