My wife and I stayed here for our first 2 nights in Buenos Aires after reading TA reviews and finding a great price online.
The rooms are massive (Wellness Premium), fresh, clean and nicely set out. The addition of the Jacuzzi and sauna were a nice touch, as was the fresh jug of juice each day.
Location wise Casa Calma is "Downtown Buenos Aires" and we found it perfect for walking up to San Telmo (superb Sunday market), down to the harbour area, Puerto Madero and over to Recoleta to stroll in the parks and cemetery.
That said, the street where Casa Calma is located, Suipacha, is narrow and exceptionally busy.... which does unfortunately make it very loud when trying to sleep, likewise when you step out the front door..... it's far from "relaxing". (Maybe the rooms at the back of the hotel are quieter).
We enjoyed our stay here but decided to stay elsewhere after returning to BA at the end of our trip.
Staff were nice and the breakfast was good. If you need to be in the Suipacha area then it's a good hotel but pack your earplugs, there are over 13m people in BA.... and a fair few of them commute down Suipacha!!More