Stayed at Hotel Impala for 2 nights during a recent business visit.
The location is great, as it is near to Plaza Libertad. The staff is helpful, especially Max, who helped me make a booking to attend a Tango show at Tango Porteno.
The only downside was the wifi was bad during my visit - poor connectivity and I had trouble getting my work done. In the end I had to go to the cafeteria across the street to get my internet connections.